Improving public accountability is currently high on the global agenda. At the same time, the organisation of health services in low- and middle-income countries is taking place in fragmented institutional landscapes. State and non-state actors are involved in increasingly complex governance arrangements. This often leads to coordination problems, confusion of roles and responsibilities and possibly accountability gaps. This study aimed at assessing the governance arrangements and the accountability practices of key health actors at the level of a Ghanaian health district with the aim to understand how far public accountability is achieved.public accountability practices, which we define as those practices that ensure direct accountability towards the public.We adopted the case study design as it allows for in-depth analysis of the governance arrangements and accountability relations between actors, their formal policies and actual accountability practices towards the public and towards stakeholders. Data were collected at a rural health district using in-depth interviews, observation and document review. In the analysis, we used a four-step sequence: identification of the key actors and their relationships, description of the multi-level governance arrangements, identification of the actual accountability relations and practices between all actors and finally appraisal of the In this rural health district with few  non-governmental organisations and private sector providers, accountability linkages towards management and partners in health programmes were found to be strong. Direct accountability towards the public, however, was woefully underdeveloped. This study shows that in settings where there is a small number of actors involved in organising health care, and where the state actors are underfunded, the intense interaction can lead to a web of relations that favours collaboration between partners in health service delivery, but fails public accountability.It is clear that new formal channels need to be created by all actors involved in health service delivery to address the demand of the public for accountability. If the public does not find an adequate response to its genuine concerns, distrust between communities and service users on one hand, and providers, international non-governmental organisations and District Health Management Teams on the other is likely to increase to the detriment of all parties’ interests.The online version of this article (doi:10.1186/s12913-016-1836-1) contains supplementary material, which is available to authorized users. The organisation and delivery of health services in low- and middle-income countries (LMIC) is taking place in a fragmented institutional landscape: not only has the number of state and non-state actors multiplied, these actors are also involved in increasingly complex multi-level governance arrangements , 2. SuchIn LMIC, health system governance is marked by power sharing between a network of government actors, international non-governmental organisations and the country’s development partners. National and international non-governmental organisations claim to represent the voice of the people . In shorOur hypothesis is that the proliferation of actors in the health system often gives rise to coordination problems and confusion of roles and responsibilities at the level of the local health system (LHS). Even if having multiple actors in a local health may contribute to its resilience, it also may possibly lead to gaps in public accountability because of power differentials. A key source of ambiguity lies in the fact that INGOs have to be accountable to multiple actors: INGOs need to balance accountability to the donors with accountability to service users , 8, 9. IIn many LMIC, the District Health Management Team (DHMT) often does not possess adequate decision space nor the capacity to effectively negotiate with INGOs. Furthermore, the access to information for donors, DHMTs and beneficiaries may be asymmetric. Finally, local health authorities often experience strong external pressures, since many actors desire rapid results within short time frames. If demands for accountability point to different directions, the question remains as to whose demands should be prioritised . SomehowIn Ghana, the strong presence of INGOs and NGOs delivering health services makes for a landscape of service provision that is interestingly complex and in which accountability is a key issue. Like most health systems, the Ghanaian health system is pluralistic and health care is delivered both through public services and a growing private sector . A majorIn this paper, we present the findings of a case study that aimed at assessing the governance arrangements and the accountability practices of key health actors at the level of a Ghanaian health district, with specific attention for (inter)national NGOs, and assessing in how far public accountability is achieved. This case study is part of a PhD study on the interactions between INGOs and District Health Management Teams and the effect on public accountability. The PhD adopted a realist evaluation approach. The initial programme theory was elicited through a meta-narrative review of the concept of accountability  and inteAs mentioned above, the PhD study adopted the realist evaluation approach, which is method-neutral: the study design needs to enable testing of the programme theory . Understthe sum of regulations, including policies, programs and decisions to remedy via a collective course of action, (2) the actors and processes that make up the collective course of action and (3) structures, including the comparatively stable institutional, socio-economic and ideational parameters, as well as the historically entrenched actor constellations that shape policy processes in a particular context.” [We briefly introduce a few key terms and their definition. We use the definition of “governance” of political scientist Zürn: “ontext.”  Under muontext.” , p.104).“(…) the obligation of public institutions and private not-for-profit organisations involved in health service delivery to answer questions regarding both decisions and actions to the public which is the source of their mandate, authority and legitimacy.” [Public accountability is a term that has different meanings according to discipline . We use timacy.” .Accountability to the public, coined by some authors as “downward” accountability, is only one category of accountability relationships among many in a health system . We coulthe interactions of (and between) SRH INGOs and the District Health Management Team in the ‘globalised’ decision space for SRH service delivery in the local health system. In effect, the decision space in the local health system consists of the network of local, national and supra-national actors involved in the organisation, management and delivery of health services. The scope of analysis is thus extended from a traditional case study, focusing on the interactions between actors at one level, to a case study of their interactions against the background of the governance arrangements and accountability practices of actors at the national and supra-national level [The case in this study is defined as the set of al level .In line with the realist evaluation approach to case selection, the cases were purposely chosen: cases should allow testing of the programme theory (PT) and are selected because they provide a variation of one or more PT elements , 33. In The local health system under study is situated in a rural district, located near a major river. It has a population of around 90,000 inhabitants spread over more than 350 villages. Most people in the district are poor. The main economic activities are subsistence farming, fishing and food hawking. There are over 25 NGOs officially registered at the District Social Affairs Office, 17 of which are currently active. Of the 25 NGOs, two are International NGOs. The other NGOs are dormant because of lack of funding . The heaWe used in-depth interviews, observations, and document review to collect data. We developed semi-structured interview topic guides for different types of respondents and these were pre-tested with SRH INGO representatives and GHS managers outside the study site. Interviewees were purposely sampled, as the objective was to collect data on perceptions of different categories of actors  operating at different levels . We conducted 23 in-depth interviews and a further 13 informal discussions with resource persons. The study was explained in detail to all interviewees, and informed consent obtained in all cases. The duration of the interviews ranged from 45 min to two hours. Interviews were recorded when allowed by the interviewee. The recorded interviews were transcribed by an experienced Ghanaian transcriber, who was bound by a confidentiality agreement.As formal DHMT-(I)NGO meetings were not held regularly during our stay, we used any opportunity that arose during the visits. For instance, we attended a half-day regional forum of the Ghana Coalition of NGOs in Health, where GHS representatives were invited to speak and a meeting between a District Chief Executive and a District Director of Health Services. Additional opportunities for observation were provided during our visits to health facilities in the district.Documents reviewed include project descriptions of SRH INGO programmes, GHS annual reports and GHS half-year performance reviews at different levels, GHS policies, guidelines and tools, reports from the district administration, policy reviews from donors and INGOs, and articles in the press.We started with drafting of a thick description of the case, incorporating data from interviews, observations and document reviews. For the analysis, we followed a sequence of 4 steps. In a first step, we described the distal context in terms of the district setting, the local health system and its health service organisation, the key actors active in the local health system, the main health concerns and the performance in sexual and reproductive health service delivery.Secondly, we analysed the multi-level governance arrangements in the local health system that affect the functioning of the District Health Management Team, the SRH INGOs and the partnerships in the local health system. These were analysed using the categories of vertical, horizontal and partnership arrangements, their purpose and main processes.A description of the account-holder and accountor roles of the DHMT, SRH INGOs and the partnerships.The identification of the main accountability linkages of each actor and assessment of their strengths: A strong relationship has intense or frequent activity and/or involves multiple processes and instruments; A relationship of moderate strength is characterized by moderate or intermittent activity and/or few processes; A weak relationship has no or virtually no activities.The categorisation of actual accountability practices: reporting, monitoring and evaluation, participatory decision-making, community consultation, supervision.The analysis of the drivers of these practices.In a third step, the actual accountability relations and practices were identified and assessed. Actual accountability practices were compared with formal (published) policies, strategies and processes. More specifically, this included:What are the actual public accountability practices and in which dimension of accountability are they nested  has the formal mandate to oversee all health activities in the district. At its heart is the core management team, in charge of the daily management and comprising of the District Director of Health Services, the administrator, the accountant, the Deputy Director of Nursing Services and the disease control officer/CHPS coordinator . The district has a population of around 90.000 inhabitants, spread around rural villages. The health district consists of six sub-districts covered by 21 public, private and private not for profit health facilities. The Ghana Health Service has one district hospital and four first-line health facilities with 13 community health zones, each with a compound (CHPS compound). Eight compounds provide curative care. The burden of disease consists mainly of malaria, schistosomiasis and non-communicable diseases. The district is a low performer in the delivery of SRH services compared to other districts in the region, primarily due to a shortage of midwives and difficult access during the rainy season. The DHMT annual report of 2012 notes a skilled delivery rate of 63.8 % and a low family planning acceptor rate of 11 %. The District Assembly will be sponsoring midwives to be assigned to the district (37).The DHMT is funded through the Ministry of Health (MOH) allocations, which are both unpredictably disbursed and insufficient to cover for all the DHMT’s activities. Two to five % of its budget is provided by the District Assembly, which in addition sponsors the training of health providers. To make up for the deficit, the DHMT takes 10 % of the internally generated funds (IGF) of the health centres. The latter consists of the fees patients pay for services and reimbursements by the National Health Insurance Scheme.The principal actors active in curative health service delivery are the Ghana Health Service and a Catholic hospital. The latter provides services comparable to a typical district hospital and its caseload equals that of the District Hospital. There is only one private first line health facility and one private maternity home.The District Assembly (DA) counts 60 members and its district administration has 45 staff, who are civil servants. The District Assembly together with the District Chief Executive represent the local government level, which is responsible for overall development planning . The DisThere are two INGOs and 1 NGO that provide or support sexual and reproductive health services. INGO 1 has been active in the district since 2000. It runs a youth recreation centre with a family planning clinic. It offers SRH counselling and services to adolescents and trains peer educators in SRH counselling. Its donor funding has dwindled over the last years.INGO 2 started a four-year maternal and child health programme in 2011, supporting behaviour change and community participation, and improvement of maternal, neonatal and child health services. This intervention is funded by an international donor and by a Northern partner organisation. It is implemented through the GHS with the support of NGO 1, a local NGO contracted to do the community-based work  .We found that the internal governance arrangements of the District Health Management Team, the INGOs and NGO 1 are mainly hierarchical in nature. The interactions between these actors are ruled by horizontal and partnership governance arrangements.Within the Ghana Health Service, strategic planning for the district is conducted every five years, combined with an annual review . The disAlso the INGOs and NGO 1 have internal vertical governance arrangements. They are all part of a national or international NGO structure, and their hierarchical management structures are reinforced by internal reporting procedures. INGO 2, for instance, has a local office that reports to the regional office, which in turn reports to the national office of the NGO. Activities can be modified during the course of programme implementation, but objectives and main strategies are fixed by the national office .The analysis showed there are several horizontal governance arrangements centred on the DHMT and the SRH INGOs. The District Health Management Team, the District Assembly, the district administration and the Member of Parliament are part of a first horizontal governance arrangement. The ongoing public sector decentralisation and de-concentration process and the gradual move towards a further integration of territorial and sector planning are the main drivers of this horizontal arrangement. Participating in this arrangement, the District Assembly is perceived by a number of respondents as playing a key role in the DHMT strategic planning . The district health plan and budget are not only sent upwards to the regional GHS level, but also to the DA, which provides small scale funding for the implementation of health programmes  and for the DHMT’s administration, staff training and infrastructure. Respondents from the DHMT and the district administration indicate that this horizontal arrangement with the DA requires skilful negotiation of the District Director of Health Services, who needs to advocate her/his case against other sector’s priorities .There is also a governance arrangement between the DHMT and the District Hospital that is mainly horizontal, although the Hospital operates virtually independently from the DHMT. The District Hospital is a separate Budget and Management Centre and receives as such its GHS resources directly and is supported by the regional level in its strategic planning .Also the governance arrangement between the DHMT and the CHPS committees is mainly horizontal and thus non-hierarchical, as the members of the CHPS committee are volunteers, including local opinion leaders, chiefs, elders, and assemblymen. The CHPS committees operate on a purely collaborative basis, and the importance of winning the community’s trust is well understood by the providers at the first line facilities. Our analysis shows that the latter often deplore the lack of community engagement in the maintenance of CHPS compounds and health facilities . It seems that both the members of the DHMT and the providers perceive the relationship with the community as instrumental, i.e. as a source of support and not necessarily as a relationship in which accountability is due in its own right.“friendly collaboration network”, not only with the District Assembly and the communities, but also with the INGO/NGOs. In practice, the Community Health Officer of the DHMT works closely with NGO 1, whereby, for example, the NGO workers take over some of the health promotion tasks of the Community Health Officer and accompany the community members to the health facility .The arrangements that exist between the DHMT, NGO 1 and the INGOs is mainly horizontal with some vertical elements. The District Health Management Team is supposed to oversee and control all health activities of the (I)NGOs, but at the same time it collaborates with these organisations, which it considers as partners. Indeed, the DHMT actively seeks to create networks among all health actors. In its annual reports, it explicitly recognises the need for a It appears from the interviews that both the District Health Management Team and the District Assembly have a high regard for INGOs and that they consider them as equal partners. INGOs are perceived as sharing the Ghana Health Service values - helping the staff to deliver on the GHS mandate through their resources and technical expertise. In addition, INGOs are much welcomed as they bring in additional resources for the DHMT . On the other hand, local NGOs are considered as less professional and requiring close supervision .Finally, we found that in this district, there are two partnerships, which can be described as collaborations with specific goals, uniting actors who each lack the resources to reach these shared goals by themselves. Partnership 1 involves INGO 1 and the District Hospital. When the donor funding for the provision of adolescent sexual and reproductive health services by INGO 1 was cut, the director of the District Hospital agreed to support the youth recreation centre and the partners signed a memorandum of understanding (MoU) to this effect.The second Partnership includes INGO 2, the DHMT, NGO 1 and the District Assembly. It was set up with the objective of improving maternal, neonatal and child health. A first Memorandum of Understanding was signed by INGO 2 and the District Assembly at district level, stipulating that the DA would provide small-scale logistical support. A second MoU was concluded between INGO 2 and the GHS at national, regional and district level. In a third step, INGO 2 subcontracted the community-based work to NGO 1. This partnership expects that the community co-manages the intervention and contributes through the community representatives in the Unit Committees, the CHPS committee members and the volunteer community mobilisers  . Our anaAccountability relations include accountor and account-holder roles. Most health actors typically combine these roles.The DHMT reports on a six-monthly basis to the Regional Health Management Team and participates in the regional performance reviews.The DHMT reports to the District Assembly on health performance.The District Director of Health Services informs the Health Sub-Committee of the District Assembly, which is part of the Social Affairs Committee, on health issues, activities and performance.The District Health Management Team is accountor to the Regional Health Management Team, the District Assembly and the District Chief Executive Fig. . The accSupervision and monitoring of providers in the CHPS compounds and health facilities.Reporting by community health nurses and nurses on performance of CHPS compounds and health facilities.Monthly performance peer reviews for providers.Participation in the hospital management meetings and hospital peer reviews .Registration and reporting of (I)NGOs to the District Health Management Team and inviting the INGOs to present their activities and performance in the DHMT performance reviews.The DHMT holds various actors to account through different practices Fig. :Supervistheir respective INGO national office on resources, activities and resultsthe District Health Management Team on resultsthe District Assembly on results.INGO 1 and 2 are accountable to different actors, enacted mainly through reporting Fig. . The INGPartnership 1, which brings together the District Hospital and INGO 1 around the youth recreation centre with the family planning clinic, reports to the national office of INGO 1 on activities and results. The Partnership also reports to the District Hospital . Finally, Partnership 1 reports to the DHMT.Partnership 2, including INGO 2, the DHMT, NGO 1 and the District Assembly, reports to the regional and the national office of INGO 2 on activities and results. The Partnership reports also to the DHMT. The Partnership finally reports to the District Assembly Fig. .Fig. 4PaFrom the analysis, it emerges that the strong accountability relationships and practices in LHS 1 are based on either vertical governance arrangements where an actor has to account to the hierarchy on results, or horizontal governance arrangements and partnerships where an actor has to account for the resources provided by another actor. Both are expressed in effective formal, regular reporting and review meetings.We found some accountability relationships to be moderately strong. We found these to occur in horizontal and partnership governance arrangements without resource exchange. In these cases, the District Health Management Team and the District Assembly are merely informed by the INGOs and the partnerships on the basis of their respective formal mandates: the DHMT is informed as overseer of health activities and the DA is informed because of its role as the state actor responsible for aligning NGO activities with local development priorities.We also found that accountability is weak when there is a power differential and/or lack of capacity. The District Social Welfare Office, for instance, has a clear mandate of regulating (I)NGOs, but lacks both the capacity and resources to effectively monitor the (I)NGOs. From our interviews, we found that this office is under-resourced and not able to supervise the NGOs active in the district.Similarly, the DHMT is supposed to oversee the District Hospital, but the latter is a relatively autonomous actor, being the largest health facility in the district, summoning the largest budget and the largest workforce.To appraise the public accountability practices of the key actors, we identified their practices and categorised them in the social, political, organisational or provider dimension . However, the actual public accountability practices they develop within these dimensions are generally weak (low ‘intensity’). In general, political representatives (the District Assembly) and other stakeholders are involved in decision-making processes, but there is no direct involvement of the communities in the decision-making processes of INGO 1, INGO 2 and Partnership 2. The same goes for the District Health Management Team. For instance, the CHPS committees are not used to ensure public accountability.We found that the public actively demands accounts of the providers and service managers and that it finds new channels to express concerns regarding health service delivery. The public airs complaints on the radio and calls the District Health Management Team in case there is a problem. Litigation related to health care appears to be also an emerging phenomenon . However, this demand of the public is not really being recognised by the key actors in the district, who prioritise accountability towards the hierarchy or to donors.In this rural health district with few (I)NGOs and private sector providers, vertical, horizontal and partnership accountability linkages are stronger than the actors’ public accountability practices, even when the public contributes to health service provision, as is the case in Partnership 2. Accountability practices embedded in vertical governance arrangements were found to be strong. However, community representatives are not directly involved in any decision-making processes of the DHMT. The CHPS committees are not functioning as a public accountability instrument. In general, there are few channels through which citizens, communities or health service users can exert a direct influence on decision-making.It is clear that some variability between the (I)NGOs is due to their organisational profile. For instance, service delivery INGOs are likely to have relatively stronger accountability processes in the provider dimension, while community-based INGOs can be expected to have strong practices in the political and organisational dimension. Our findings seem to confirm the theories of Edwards and Hulme, who found INGOs to balance multiple accountability streams, with accountability towards communities losing out against demands from other stakeholders .The partnerships in this district have few public accountability practices. This confirms the view of Esmark, who contends that accountability within partnerships tends to overshadow accountability to actors outside of partnerships .Our findings indicate that within the DHMT’s processes, there are no structural arrangements for public involvement in decision-making. The district health committees attached to the DHMT, foreseen in the Ghana Health Service and Teaching Hospitals Act of 1996 , appear networks” of accountability [“informal accountability” practices [“spontaneous accountability” emerges between actors who are connected through both professional and other relationships [public accountability.In this district, we identified accountability practices that are based on the mechanism of persuasion, and that are embedded in horizontal governance arrangements. Our findings corroborate the theories of Sorensen and Torfing  and Mulgtability . Such hotability , 46. Exaractices , 48. It ionships . Intenseionships , 51. NevThis case study has some limitations. We encountered issues in relation to gatekeeping in organisational settings as described by Burnham . Some reWe agree with Fontana and Frey that both the interview and the interpretation of the event is socially constructed and contextual, influenced by the perceptions of both the interviewer and interviewee . As discIn this case study, we identified the key actors in public accountability in the field of health, identified their governance arrangements and the accountability practices, and mapped the accountability relationships. We found that the accountability towards the public was woefully underdeveloped. This study confirms that in settings where there is a small number of actors involved in organising health care, and where the state actors are underfunded, the intense interaction leads to a web of relations that favours horizontal accountability but fails public accountability. It is clear that new formal channels need to be created by the GHS or the INGOs to address the demand of the public for accountability. If the public does not find an adequate response to its genuine concerns, distrust between communities and service users on one hand, and providers, INGOs and DHMT on the other is likely to increase to the detriment of all parties’ interests.


Widely used information diffusion models such as Independent Cascade Model, Susceptible Infected Recovered (SIR) and others fail to acknowledge that information is constantly subject to modification. Some aspects of information diffusion are best explained by network structural characteristics while in some cases strong influence comes from individual decisions. We introduce reinvention, the ability to modify information, as an individual level decision that affects the diffusion process as a whole. Based on a combination of constructs from the Diffusion of Innovations and the Critical Mass Theories, the present study advances the CMS  model which accounts for the interplay between network structure and human behavior and interactions. The model's building blocks include processes leading up to and following the formation of a critical mass of information adopters and disseminators. We examine the formation of an inflection point, information reach, sustainability of the diffusion process and collective value creation. The CMS model is tested on two directed networks and one undirected network, assuming weak or strong ties and applying constant and relative modification schemes. While all three networks are designed for disseminating new knowledge they differ in structural properties. Our findings suggest that modification enhances the diffusion of information in networks that support undirected connections and carries the biggest effect when information is shared via weak ties. Rogers' diffusion model and traditional information contagion models are fine tuned. Our results show that modifications not only contribute to a sustainable diffusion process, but also aid information in reaching remote areas of the network. The results point to the importance of cultivating weak ties, allowing reciprocal interaction among nodes and supporting the modification of information in promoting diffusion processes. These results have theoretical and practical implications for designing networks aimed at accelerating the creation and diffusion of information. Complex networks are characterized by emergence and self-organization dynamics, in which local decisions and interactions accumulate into system-level phenomena. The diffusion of information in complex networks is propelled by decisions made at the local level of individual nodes to consume and share the information, but, as identified by Christakis and Fowler , 2 the oWidely used Information diffusion models often use simplifying assumptions in order to describe complex phenomena. For example, models such as Susceptible-Infected-Recovered (SIR)  or Susceactors comprising the network; (2) content, or properties of the information itself; and (3) the underlying network structure. By combining all three, the present work offers comprehensive understanding of the dynamics of information diffusion.We suggest that information diffusion involves a process that is affected by a combination of three factors: (1) the before passing it on. In this context, we present the concept of reinvention adapted from the Diffusion of Innovations (DOI) Theory. Reinvention, i.e. modification of information, is considered on two levels: as an attribute of the information itself, allowing an investigation of whether it enhances or diminishes the value of information as it spreads in the network; and as a behavior performed by nodes in the network. The dynamics involved in modification activity shed light on whether the act of modifying information has an accelerating or decelerating effect on diffusion. The third factor of network structure relates to whether the network is directed  or undirected , as well as to the tie strength between nodes.Regarding the actors, we present a two-stage decision making process that involves volition: the decision to consume information, and upon consumption, whether to pass it on. Regarding content, actors have the option to transmit the information "as is" or, to modify it The present work offers an agent based model that accounts for volition and possible changes information undergoes throughout the diffusion process. The model combines theoretical constructs from the Diffusion of Innovations Theory  and CritThe model is applied on the social graph of three distinct networks: DBLP network of research scientists, US Patent citation network and Wiki Talk network of conversation. These networks share the purpose of information dissemination, but, they differ in the communication patterns they support: while the DBLP is an undirected network that allows reciprocal communication, US Patent and WikiTalk are directed networks supporting one-way communication. The question motivating this research is: How does the interplay between individual decisions and structural network properties such as direction and tie strength affect the diffusion of information in networks?Our findings imply that the modification of information has a varying effect throughout the diffusion process. While having a negative effect on attaining the inflection point, it has a positive effect on overall diffusion, as modified information propagated in the network longer, reaching a higher percentage of nodes positioned further in the network than information that is shared "as is". Furthermore, our findings indicate that the greatest effect of modifications on diffusion is found when communication is reciprocal (undirected) and when information is shared via weak ties. These findings question and fine-tune Rogers' diffusion model and traditional information contagion models.The rest of the paper is structured as follows: we begin theory development by presenting known models of information diffusion and explain the need for accommodating the human aspects of volition and modification. We then describe the main constructs of the Diffusion of Innovations Theory and the Critical Mass Theory and introduce the manner by which tying those two theories together leads to the consume-modify-share (CMS) model for information diffusion. Next, we describe the research questions, data used, method and the results obtained. The paper continues with a discussion that outlines the research contribution to theory and concludes with addressing limitations and identifying areas for future research.Widely used information diffusion models such as Independent Cascade Model , 9; ContOther models, such as the Threshold model  assume tThreshold models gave way to a line of research dealing with maximization calculations and network influence models focusing on how to effectively trade-off the cost of seeding  and the size of the cascade generated. Contagion and threshold models assume information diffuses from its originator in a multi-step process that gradually reaches a large number of individuals.Recently, the study of complex networks has distinguished between interacting network layers, giving rise to research on multi-layered networks , 14, 15.Interesting research on SIR and SIS modeling of epidemics in complex networks indicates that the existence of a critical threshold is correlated with the topology of the network , 17. WhiNevertheless, epidemiological and threshold models, when adapted to model the diffusion of information, do not capture the unique properties of information such as: (1) information is not synonymous with disease and therefore exposure to it is not enough for it to spread. Although senders of information can send information indiscriminately (such as junk mail), receivers of new information are faced with two decisions that existing models fail to address: the decision whether to consume the information, and upon consumption, the decision whether to pass it on to others. Explicit retransmissions are vital for information to spread and reach exposure to a critical mass of people, (2) in most models, the entity being spread  is assumed to be invariant during the diffusion process. Yet in realistic situations, information is prone to modifications as it diffuses. Modifications can be enhancements or deletions, intentional or erroneous. They may add or diminish value from information , 19. (3)content, by sender/receiver motivations and by network structure. From the content perspective, researchers have identified the following influences on the decision to consume and share information: emotional appeal . Furthermore, Rogers points out that "unless the client feels so involved with the innovation that they regard it as theirs, it will not be continued over the long term". Modification, in this context, manifests a level of involvement. CMT's production functions offer a rich explanation regarding the dynamics involved. According to CMT, accelerating and decelerating social dynamics determine the extent and sustainability of the diffusion process. In this light, we turn attention to the sustainability of the process beyond the inflection point, and ask: P2: The influence of individual behavior on the reach of information is affected by (a) network directionality and (b) tie strength.P3: The influence of individual behavior on sustainability of the diffusion process is affected by (a) directionality of the networks the (b) tie strength between nodes sharing information.innovation's attribute as the fourth element involved in diffusion research. When information diffuses it is susceptible to change which affects its perceived value. The analysis of production functions allows determining whether modifications enhance the value of information that spreads in the network and if so, which modification type contributes to the process. This leads to an additional fine tuning of the research question: How does the interplay between individual behavior (modification) and structural properties affect the overall value of information that spreads in the network? We propose:Lastly, Rogers describes the P4: The contribution of modification to the value of information that diffuses in the network is higher in undirected networks than in directed ones.P5: The contribution of modification to the value of information that diffuses in the network is higher when shared via weak ties than when shared via strong ties.In order to test information flows in a realistic topology, data is comprised of three actual networks harvested from the web: DBLP network of research scientists, Wiki Talk network, and the US Patent citation network. These networks provide a diverse source of data as they vary in properties such as size, mean degree and direction.DBLP computer science bibliography, retrieved from the SNAP website [undirected network.The  website , is a coWiki Talk (Wiki): retrieved from SNAP [directed edge from node i to node j represents that user i edited a talk page of user j at least once.rom SNAP , is a neUS Patent citation network retrieved from SNAP [directed both in the direction of the flow of information and temporally.rom SNAP  includesAs seen in Agent-based modeling (ABM) is a computation analysis tool used for simulating system dynamics when the system consists of multiple autonomous and interacting components, or "agents". Each agent follows a set of rules that can be either identical for all agents (homogenous) or different from agent to agent (heterogeneous). ABMs are often applied to validate individual-level configurations by reproducing patterns that result in the system level.In the social sciences, ABM has become increasingly popular as it enables to build models representing individual entities and their interactions. By offering the possibility of modeling individual heterogeneity and an explicit representation of agents' decision rules, these models represent multiple scales of analysis and the emergence of macro structures from individual action . ABM's aThe present model incorporates the decisions to Consume, Modify and Share information; therefore, we name it the CMS Model. CMS is an agent-based model constructed using MATLAB version 7.12). The model is based on discrete step iterations to demonstrate the influence of modifications on the process of critical mass formation and the overall diffusion of information. The CMS model incorporates theoretical constructs based on prior literature , 7, 48, .12. The Nodes in the network were assigned various probabilities for each of the following states:before receiving informationreceived information but did not consumeconsumed without modifying, then did not shareconsumed and shared without modificationconsumed and modified but did not shareconsumed, modified, and sharedThe model was run on the flow of information between nodes without performing modification and then again with modification, in order to isolate the unique effect of information modification. After simulating different starting points, peripheral and central nodes, we chose the option that showed the greatest variance in results: the weakest neighbor of the most connected hub.Each starting node received a standard assignment of value of information set to V = 1 at the beginning of the experiment. Modification was either constant (AM) or relative (RM), corresponding, respectively, to decelerating or accelerating production functions. Each node modified the information independently, yet the simulation allowed the study of the collective outcome.The dynamics start to evolve by the starting node’s neighbors who are the new receivers of information. Information arrives with a certain value assignment according to the node state detailed above. Each new receiver node "decides" what to do with incoming information based on the probabilities assigned to various possible actions. In particular, each node decides whether to consume, modify, and then whether to share the information with its neighbors .Each decision phase constitutes one experiment iteration. The new state obtained leads to continuing the sharing of information according to the model rules. Modifications occur upon consumption of information before the decision to share. The process is repeated by finding the new receivers. Iterations repeat until final resolution when information cannot continue to flow between nodes, and the network reaches its final state. At this point, we assess whether critical mass was reached, the magnitude of collective outcome, and the degree of spread.The number of iterations needed before convergence depends on the network diameter and density. In order to get representative results and verify sufficient simulation results to extract average measures, we simulated the full process of information flow and repeated the full experiment thousands of times, for each set of parameters (with and without modification): DBLP: 2,000, Wiki Talk: 5,000, US. Patent: 200,000. Such large numbers are needed in order to allow a high resolution histogram since many decisions of nodes in the model are probabilistic.The parameter describing the flow of information in the network is the probability of consuming information, which depends on the tie strength between two nodes and is proportional to the intensity of the connection. Tie strength in the Wiki Talk network is inferred from the number of edits, in the Patent network from the number of citations and in DBLP from the number of co-authored papers. For each network the probability for consuming information is calculated in a manner that reflects either weak or strong ties and is based on the assumption that information received from a strong tie will be consumed with higher probability than that received from a weak tie. As each network has unique direction, degree and tie strength distribution, we performed sensitivity tests and determined the probabilities of consumption to be the lowest probability for a diffusion process in that specific network up to reaching super spread. A super spread is defined as a situation in which at least 20% of the nodes in the network consume the information.In addition to tie strength, consumption is related to the value of information. To allow comparison between consecutive simulations, the initial value of information is set to 1 (denoted by the letter V). The value of information changes during its spread due to modification activity. The following formula shows how value influences the probability of information consumption.In accordance with CMT, the value of information is affected by the modifications it undergoes. Modifications can be either constant  or relative .A 20% change in the value of information is chosen to reflect a change that is "modest" and realistic, that is, neither negligible (e.g. 5%) nor too dominant (e.g. 75%). The simulation randomly assigned a positive and a negative change with a 50% chance, to prevent bias. This assumption could easily be relaxed, to allow the study of asymmetric diffusion processes, but we leave this to future research.consumption above. It regards the probability to share information as higher when reinvention occurs, even when it lowered the value of information . In the simulation, we take the absolute value of the RI modification.According to Allsop, Bassett & Hoskins  there isWillingness to share = 60%The chance to modify information is calculated independently for each consumer. According to Rogers, Innovators comprise 2.5% of the social system. One option we considered was to allow only the first 2.5% of consumers (the innovators) to do all the modification and then stop it completely. However, based on Rogers' categories, we assigned the innovators a 25% chance to modify and a 2.5% probability of modification to the rest of the nodes.Modifications added to or subtracted from V on a 50% chance basis.Modification: Positive or negative modification of original informationRelative modification (RM): Adding or subtracting 20% from the value of information with each modification, simulates an accelerating production function.Absolute modification (AM): Adding or subtracting a constant value set to 20% of the initial value of information at the starting point. This simulates a decelerating production functionTie strength: Inferred from the frequency of joint activity [activity , 34, 49Degree: Represented by average node links [de links Network directionality: Directed or undirectedCritical mass: Average number of nodes sharing information until an inflection point is reachedInformation reach: Average number of nodes receiving information at the end of the diffusion processSustainable diffusion: Number of iterations following the inflection point until terminationCollective outcome: Total value of information normalized per number of nodes that have consumed itThe finding that in 52–78% of the cases information is not consumed by receiving nodes strengthens our notion that exposure to information is not enough for it to spread. The low percentage of cases in which modified information is shared is surprising considering the effect modification has on overall diffusion, as will be explained further on.Rogers  defined sooner in the process than the 16% anticipated by Rogers. In the No Modification (NM) scenario, an inflection point occurs on average when 3.3% of nodes are involved in the process when shared via weak ties, and when shared via strong ties, 12.6% of nodes. In the Relative Modification (RM) scenario–when transmitted via weak ties, on average 4.9% of nodes are involved in the realization of the inflection point, and 13.6% when transmitted via strong ties. Looking at the Absolute Modification (AM) scenario, 4.5% of nodes on average are involved when information is shared via weak ties, and 13.7% when shared via strong ties. Proposition 1(a) is supported together with an unexpected result–in all three networks, modification delayed reaching an inflection point as a higher percentage of nodes are involved in the diffusion process when information is modified.Interestingly, an inflection point occurs Regarding Proposition 1(b), the effect of modification on reaching the inflection point is stronger in the undirected network, but in a negative sense. The percentage of nodes required to reach the inflection point in the undirected network, DBLP, is 1.6 times higher when modification takes place, while only 1.1 times higher in the directed networks, Wiki Talk and US Patent. Proposition 1(c) is accepted as well—as the realization of the inflection point is affected by the tie strength.The percentage of nodes involved in the realization of the inflection point is presented in Looking at the interplay between tie strength, directionality and modification we found that in DBLP (undirected) and Wiki Talk (directed) the type of modification interacts with tie strength in a similar manner–in weak ties, relative modification (RM) had a stronger effect. In strong ties–the absolute modification (AM) had a stronger effect. This difference implies that when transmitted via weak ties, modification done in subsequent stages of the diffusion process has a stronger effect on diffusion than that done in its initial stages. When transmitted via strong ties, it is the opposite–initial modification carries a more pronounced effect than modification in later stages of the diffusion process. No difference between the types of modification was found in the Patent network. This may be due to the overall smaller scope of diffusion in this network—less than 8% in the case of strong ties, and less than 1% when weak ties are transmitting information.The effect of modifications on the realization of the inflection point is analyzed by an additional measure: the number of iterations required for attaining this point in the diffusion process. As seen in These findings suggest that the effect of information modification is influenced by the rate of diffusion. As diffusion is abrupt in strong ties, modifications occur mainly in the initial stages, and thus are more effective than later on. When transmitted via weak ties, diffusion is slower, allowing subsequent modifications to take place. In the Patent network the overall effect of modification is negligible as diffusion is smaller in scope.Propositions 3 and 4 concern the effect of modifications on overall diffusion in terms of reach and sustainability. Reach is measured by the percentage of network nodes information has reached at the end of the diffusion process. Sustainability is inferred from the number of iterations required for information to reach a final spread in the network. The higher the number of iterations, the longer information propagates within the network, thus implying a sustainable process.Reach. In all three networks, regardless of tie strength, modified information reached a higher percentage of nodes in the network than unmodified information. Comparing the networks reveals that the most pronounced effect of modifications is in the DBLP network which is undirected. In this network, when shared via weak ties, modified information reached 2.7 times more nodes than unmodified information. In the two directed networks modified information reached 1.2 times more nodes. Proposition 2a is accepted–the influence of individual behavior on the reach of information is affected by the directionality of the networks.Regarding the effect of tie strength on diffusion, information shared via strong ties reached a higher percentage of nodes in the networks than that shared via weak ties. Interestingly, we found that when modifications of information take place, the difference in reach in strong and weak tie scenarios shrank, especially when it was modification of the relative type. In In order to further verify the effect of modifications on reach, we performed an additional analysis to determine the depth of reach. We were interested whether modified information transmitted via weak ties not only reached a higher percentage of nodes, but also nodes located in the periphery of the network.Location is associated with degree: peripheral nodes have fewer connections, i.e. a lower degree measure than central nodes. The analysis was carried out by calculating the average degree of nodes involved in the diffusion process.A comparison of the average degree of nodes at the end of diffusion is presented in Note that the stronger effect of modification on reaching remote nodes is found in the undirected DBLP network. Summarizing Proposition 2: the structural properties of direction and tie strength influences individual behavior and result in varying degrees of information reach within the networks.Sustainability. Sustainability is inferred from the number of iterations required for information to reach a final spread in the network. The higher the number of iterations, the longer information propagates throughout the network, thus implying a sustainable process.Regarding Proposition 3a, the effect of directionality on the sustainability of the diffusion process is evident: in the undirected network of DBLP the diffusion process is more sustainable than in the directed networks of WikiTalk and US Patent.Modifications as a whole contributed to the sustainability of the diffusion process across all networks analyzed: modified information of both value change schemes propagated in the networks longer than unmodified information.Considering Proposition 3b, the effect of modification is minor in the directed networks in both tie strengths, but is significant in the undirected network especially when assigned a relative value modification and transmitted via weak ties. In this case information propagated in the network up to 4 times longer than information that has not been modified.When comparing the effect of tie strength an interesting phenomenon arises: in the DBLP and Wiki networks the diffusion process is more sustainable when information is shared via weak ties than in strong ties. In the Patent network, it is opposite.In summary of Propositions 3 and 4, the contribution of modifications to the reach and sustainability of the diffusion process is stronger in the undirected network than in the directed ones. The interplay between tie strength and information modification is found mostly in the undirected network, in which its effect when shared via weak ties is prominent. In the directed networks the effect of modification on sustainability in both tie strengths is negligible. Modification with a relative change (RM) is evident in the undirected network, DBLP, especially when information is shared via weak ties. In both directed networks relative and absolute modification have a similar effect on reach and sustainability.While Rogers  identifiCollective outcome. The spread of valuable information in a network is a desirable collective outcome for members of the network. As such, the contribution of modification to the value of information that diffuses in the network is of interest and is addressed in regard to directionality (P4) and tie strength (P5) by plotting the cumulative value of information that spreads in the network (Y axis) versus the number of consumers (X axis) in Figs In the DBLP, which is undirected, modifications enhanced the value of information in both tie strengths as indicated by the green and blue lines in In the WikiTalk network , modificIn the Patent network, modifications contributed to the value of information in both tie strengths, with a stronger effect by initial modifications than by late modifications.Referring to Proposition 4, in the context of the collective value of information, the most prominent difference between directed and undirected networks lies in the dynamics of modification activity. In the undirected network modifications happened repeatedly with subsequent nodes contributing more to the value of information than initial nodes, thus implying an evolutionary process for information throughout the diffusion. In the directed networks, modifications appearing in the initial stages of diffusion contribute more significantly to the value of information.Regarding the interplay between modification and tie strength, Proposition 5 is partially supported, as the contribution of modifications to the value of information is greater when information diffuses via weak ties than via strong ties in both DBLP and WikiTalk networks, but does not have an effect in the US Patent network.This study evaluated information diffusion dynamics by combining global network structural aspects with local decisions and actions taken by nodes.Many widely used models describing diffusion of information are built on assumptions that, to our understanding, underestimate the complexity of the decisions taking place. Furthermore, models need to address the manner in which micro level behaviors aggregate to macro diffusion processes. By combining expressions from the DOI: communication channels , communication proximity (tie strength), individual behavior (modification of information) and the inflection point with CMT concepts: accelerating and decelerating production functions manifested in group processes, we address local (micro) and network (macro) points of view.The challenge in designing the model was to address the diffusion of information in a manner that accounts for (a) modifications information undergoes throughout its spread; (b) the complexity of differentiating between consuming and sharing information; and (c) structural properties. These challenges are addressed by the proposed model: Consume, Modify, Share (CMS).The model was applied to the graph of three actual networks harvested from the web, thus providing a means to test information flows in a realistic topology. The networks analyzed were the DBLP network of research scientists, Wiki Talk network, and the US Patent citation network. As these networks vary in structural properties such as direction, size, mean degree and node-link ratios, they provide diverse sources of data that may enrich our understanding of the interplay between structural properties and individual decisions and their effect on diffusion of information in networked settings.The finding that in 52–79% of the cases information is not consumed by the receiving nodes  supportsIn directed networks spread and reach of information is limited compared to undirected structure . Our resAs diffusion progresses the effect of directionality on diffusion processes increases. In the initial stages of diffusion, up to the inflection point, directionality has a minor effect. In later stages of diffusion, when social dynamics evolve, the effect of directionality increases.Regarding the interplay between modifications and directionality: up to the inflection point, regardless of directionality, modification has a minor effect on the number of iterations needed and percentage of nodes involved in the process. It is in the longer process of reaching full spread that differences between network types become evident. In this process, two parameters were evaluated: sustainability (the number of iterations required to attain full spread) and reach (the percentage of networks information has reached). Regarding sustainability, the effect of modification on the number of iterations to final spread was minor in both network types when information was shared via strong ties. When shared via weak ties, the difference between directed and undirected networks was robust. In the undirected network, there was a 227% growth in the number of iterations when modifications occurred in weak ties, as opposed to 2.4% in the directed networks.Regarding reach, in the directed networks, modification is found to have a negligible effect on reach, with no distinct difference between the two value schemes assigned to modifications. In the undirected networks, the effect of modification on reach is pronounced, especially when information is shared via weak ties and assigned a relative value.A note regarding the US Patent network is in order. Based on the temporal nature of citing, in which patents can only cite earlier patents, all edges in the network point backwards, thus forming a directed, temporal, acyclic graph. In this network, diffusion is limited: unmodified information reaches 7% of the network when shared via strong ties and less than 1% when shared via weak ties. Although modifications took place in 8% of the cases–the highest percentage of all three networks studied–it had a negligible effect on diffusion, with no difference between relative and absolute value schemes assigned to modified information. The combination of the direction and temporality thus appears to be unfavorable for information diffusion.When connections in the network are asymmetrical (directed networks), social benefits such as building social ties, prestige and influence, may be achieved by publishing original information, and not so much by the cooperation and dialogue that modification affords. Symmetrical connections (undirected networks) built on reciprocity and dialogue serve for building social ties, prestige and influence through conversation. Modifications appear to be a type of "conversation" that is appreciated in this network type: modified information propagated in undirected networks for a considerably longer time and reaches isolated nodes that otherwise would not have been involved. Thus, the underlying connectivity patterns that directionality entails drive the social aspects of communication.type of information, i.e., weak ties play a role in transmitting unique and novel information [speed of diffusion, which is associated with strong ties; and the reach of diffusion, which is associated with weak ties [Analyzing the interaction between tie strength and the act of modifying information yields interesting observations. In the literature, tie strength is associated with the ormation , 52; theeak ties , 43, 53.While DOI concentrates on the rate of diffusion, CMT focuses on the preconditions for sustainability. This work adopted the latter emphasis and accordingly tended to focus on sustainability, which is inferred from the number of iterations required for information to reach full spread. Findings show that weak, rather than strong ties contribute to the sustainability of the diffusion process as information transmitted by the former remains longer in the network. When modification occurs, the contribution of weak ties grows substantially, but only in undirected networks.Turning to reach, present findings contradict previous findings in which weak ties are associated with reach. Across the networks studied, information transmitted via strong ties reached a higher percentage of nodes than that shared via weak ties. As seen in Looking at the breadth of diffusion, modified information shared via weak ties is found to have a pronounced effect. This finding emerges by calculating the average degree of nodes involved in the diffusion process with and without modifications. Degree is associated with location: peripheral nodes are less connected and, naturally, have a lower degree count than central nodes in the network. As seen in In addition, an interesting interplay between tie strength and the type of modification taking place surfaced: when transmitted via strong ties, modification of the absolute type carries a stronger effect, and when transmitted via weak ties, it is modification of the relative type that is stronger. This holds true for reach measurements throughout the diffusion process: up to, and following the inflection point. This interaction suggests that in the strong tie scenario the initial nodes performing modification that have a stronger effect on reach, and in the weak tie scenario it is modification performed by subsequent nodes that has more impact. It is through weak ties, then, that diffusion accelerates to the degree required for sustainable diffusion.The absolute and relative value change schemes assigned to modified information simulate negative and positive interdependence dynamics between nodes. Absolute value (AM) simulates negative interdependence, decreasing the rate and likelihood of contributions. Relative value (RM) simulates positive interdependence. The negative interdependence found when modified information is shared via strong ties implies that the initial modification has the greatest effect on the value of information, while subsequent nodes have an incremental effect. This supports the observation that strong ties are homophilious, while weak ties are heterophilious in nature , 54. Thuduration and reciprocity.Modifying information has a positive contribution to the diffusion process in terms of sustainability and reach. The most pronounced effect of modifications is found in the undirected networks when information is shared via weak ties and assigned a relative value. This finding contributes to identifying the primary conditions required for modifications to have a substantial effect to be Regarding duration, for modifications to be effective a long diffusion process is needed. Longer diffusion allows higher incidence of modifications promoting the evolutionary process that makes information more attractive to a greater variety of nodes in the network. Diffusion is longer in undirected networks enhancing the effect of modifications. In addition, weak ties slow down diffusion explaining the stronger effect modification has when shared via weak ties. The stronger effect of relative modification suggests that the slower rate of diffusion in weak ties allows information that is modified to undergo an evolutionary process in which it enhances the value of information that spreads in the network, with subsequent nodes being more influential on attaining higher value than initial nodes.Regarding the second condition, reciprocity is a key concept for understanding social interactions . ReciproIn all three networks, when shared via weak ties, modifications enhanced the value of information that spread throughout the network. While modifications occurred in the directed networks at the beginning of the diffusion process and then ceased  the CMS model offers new knowledge on information diffusion and the special role of the decision to modify information. In addition, we identified nuanced observations regarding Rogers' assertions about the inflection point and the manners in which the CMS model contributes to Critical Mass Theory. In the following we unpack these two contributions.The definition of the inflection point and its relevance to a sustainable diffusion: in the case of digital networks, our finding questions the identification and contribution of the inflection point to the diffusion process as introduced by Rogers . Tie strThe inflection point was identified by Rogers as a determinant for diffusion to become self-sustained. We found the diffusion process became self-sustained as soon as a hub shared information and termed this as "the point of no return". Identifying the "point of no return" spun our attention to the definition offered by CMT regarding "critical mass"—the identification of the initial group of nodes needed for the diffusion process to become self- sustained.alone can comprise the critical mass needed for attaining vast diffusion, as long as they are friends of hubs.CMT defines the critical mass as the "small segment of the population that chooses to contribute to the collective action thus creating conditions for the majority to join leading to the achievement of the collective good" . When loThis finding is in accordance with Dezso & Barabasi's  observatCritical Mass Theory emphasizes the role played by heterogeneity of resources and interest levels on attaining the critical mass of initial participants in a diffusion process. CMT has been criticized on three main grounds: (a) The simulations it is built upon mainly address situations involving an accelerating production function, thus failing to capture the complexity of situations that entail decelerating production functions ; (b) TheThe present research addresses these points. We demonstrate the theory’s applicability in a multi-step diffusion process with accelerating and decelerating production functions, while taking tie strengths, i.e., relative weights of contributors, into due consideration.Applying the dynamics of production functions to the diffusion of information in networks contributes to the understanding of the dynamics associated with sharing information. As production functions imply interdependence that can be positive (accelerating) or negative (decelerating), they can be used to infer node behaviors in networks and manifest the manner in which node-related behaviors aggregate into global network effects. For example, the interaction found between type of modification  and tie strength sheds light on communication patterns in social networks.Adapting CMT to the diffusion of information in networks broadens the theory's usage and theoretical implications. Adapting its main constructs to those used in social network analysis–for example, using degree as a surrogate measure for resource and using tie strength as a surrogate measure for interest–opens new opportunities for contemporary studies that rely on CMT.Diffusion of information is a complex phenomenon that involves, at the actors' level, a two- stage decision process: the decision to consume information and the decision to share it with others. It is through retransmissions (re-sharing) performed by network nodes that information diffuses. Both stages are influenced by an array of factors that involve image , communiGoing back to diffusion as synonymous with contagion, as suggested by epidemiological models such as the Susceptible-Infected-Susceptible Model  and the In modeling diffusion, the unique properties of information need to be addressed. These include the ease in which it can be shared , the subjective value it carries , and theFurthermore, information diffusion models view the decision to adopt or consume information to be binary: nodes are either "infected" or not, either "adopt" or not. Treating information as prone to modifications widens the possibilities for potential adopters, thus allowing a middle way–to consume information and share with modifications, as common in today’s prevalent participatory culture .The CMS Model introduced here contributes to existing models in that it encompasses the actor, content and structure components that influence the diffusion of information. By combining all three, the dynamics involved in diffusion processes are addressed at the personal and global levels, offering preliminary insights into the way network structure affects the behavior of nodes.The finding that modification involves positive interdependence between weak ties and negative interdependence when shared via strong ties sheds light on factors that contribute to the sustainability and reach of the diffusion process. In addition, the model reveals that modifications have a varying effect throughout the diffusion process: negative up to the inflection point, and positive effect on overall diffusion. This finding turns attention to the role subsequent stages of the diffusion process play in the success of diffusion, which opens new opportunities for the study of maximizing diffusion. Designed to address the unique properties of information, the CMS model may be used to study additional variables associated with the diffusion of information such as social influence, interactivity, WOM dynamics, gender inclinations, etc.The CMS model presented here was designed with best intentions to simulate real world decision making regarding the spread of information in networks. Still, the model suffers from some limitations. Starting with simplification, by synthesizing the variables into a single numeric value our results point out general directions or trends and not absolute values. In our analysis we took care to discuss relative outcomes, but not absolute values.In addition, we followed Roger's observation of innovators comprising 2.5% of the network and assigned innovators randomly, not by their structural properties in the network. In future work, it will be interesting to align network structure and attributes associated with the specific innovativeness levels.Our model allowed nodes to receive information once, implying that the effects reported here are probably conservative. Further research may incorporate the opportunity of multiple possibilities to receive and consume information. Additional and varied starting points as well as multiple simultaneous starting points should be examined to further understand the effect of network structure on the diffusion of information. Future research will address the interplay between modifications and additional structural properties such as density and clustering coefficient. Lastly, studying three networks gave us a rich mosaic of observations, but our findings are not "universal" therefore more networks need to be researched.S1 Dataset(TXT)Click here for additional data file.S2 Dataset(TXT)Click here for additional data file.S3 Dataset(TXT)Click here for additional data file.S4 Dataset(TXT)Click here for additional data file.S5 Dataset(TXT)Click here for additional data file.S6 Dataset(TXT)Click here for additional data file.S7 Dataset(TXT)Click here for additional data file.S8 Dataset(TXT)Click here for additional data file.S9 Dataset(TXT)Click here for additional data file.S10 Dataset(TXT)Click here for additional data file.S11 Dataset(TXT)Click here for additional data file.S12 Dataset(TXT)Click here for additional data file.S13 Dataset(TXT)Click here for additional data file.S14 Dataset(TXT)Click here for additional data file.S15 Dataset(TXT)Click here for additional data file.S16 Dataset(TXT)Click here for additional data file.S17 Dataset(TXT)Click here for additional data file.S18 Dataset(TXT)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.


In many low- and middle-income countries, community health volunteers (CHVs) are employed as a key element of the public health system in rural areas with poor accessibility. However, few studies have assessed the effectiveness of CHVs in improving child health in sub-Saharan Africa through randomized controlled trials. The present study aims to measure the impact of health promotion and case management implemented by CHVs on the health of under-5 children in Ghana.This study presents the protocol of a cluster-randomized controlled trial assessing the impacts of CHVs, in which the community was used as the randomization unit. A phase-in design will be adopted, and the intervention arm will be implemented in the intervention arm during the first phase and in the control arm during the second phase. The key intervention is the deployment of CHVs, who provide health education, provide oral rehydration solutions and zinc tablets to children with diarrhea, and diagnose malaria using a thermometer and a rapid diagnostic test kit during home visits. The primary endpoints of the study are the prevalence of diarrhea and fever/malaria in children under 5 years of age, as well as the proportion of affected children receiving case management for diarrhea and malaria. The first and second rounds of household surveys to collect data will be conducted in the first phase, and the final round will be conducted during the second phase.With growing attention paid to the roles of CHVs as an essential part of the community health system in low-income countries, this study will contribute valuable information to the body of knowledge on the effects of CHVs.ISRCTN49236178. The online version of this article (doi:10.1186/s12889-016-3991-z) contains supplementary material, which is available to authorized users. Despite the substantial progress made between 1995 and 2015, over half of the deaths in children under 5 years of age in sub-Saharan Africa are still caused by malaria, diarrhea and pneumonia .Of the 62,000 deaths among Ghanaian children under 5 years of age in 2013, the majority were caused by malaria (20%), acute respiratory infections (13%), and diarrhea (8%) . While oGlobally, given the limited human resources in the health sector, a community-based approach has been promoted as a cost-effective and pro-poor intervention to improve the accessibility of health care , 6. CommIn Ghana, the Community-based Health Planning and Services (CHPS) initiative was adopted in 1999 as a national policy establishing a community health system to improve the accessibility and affordability of health care for residents in the remote areas . A distiA number of studies have demonstrated that community-based health systems, particularly those involving CHWs, have led to improved access to maternal healthcare services –15, modeTherefore, there is need for research testing the impact of CHWs, specifically regarding the promotive and preventive roles in major childhood illnesses in sub-Saharan Africa.The study aims to measure the impact of CHVs on reducing childhood illnesses, especially malaria and diarrhea, in Ghana, which is one of the countries that has implemented a CHW program. We plan to explore the impact of CHVs, especially with regard to their role in the provision of health promotion, first-aid management for diarrhea with oral rehydration solution (ORS) and zinc tablet, early diagnosis of malaria using rapid diagnostic tests (RDTs), and referrals for further treatment.kente (a specific type of silk and cotton fabric that originated in the Ashanti Empire), with a few government workers interspersed among the population.The Ketu South district is one of the 25 administrative districts in the Volta Region, located in the southeastern corner of Ghana See Fig. . The KetIn the study, the community was taken as the randomization unit, because we expected that CHV activation will impact disease prevention and treatment among households within a given community, which is where people interact with one another most closely. All interventions related to CHV activation will be performed at the level of each community. A phase-in design will be used for the study. CHVs will be activated in the intervention arm during the first phase, and a comparable intervention will be performed in the control arm during the second phase.ISRCTN49236178/http://www.isrctn.com/ISRCTN49236178).The study was approved by the Ghana Health Service Ethics Review Committee under the Ministry of Health, Republic of Ghana , and registered as an international standardized RCT on June 16, 2015 . An intermediate indicator for child malarial prevalence is the utilization of insecticide bed nets the previous night while sleeping.We are going to carry out a process evaluation along with the impact evaluation to investigate dose delivered and dose received. First, logbooks will be recorded by CHVs themselves and signed by caregivers, where we can assess how many key messages have been delivered at each household level. Second, four rounds of household survey will be conducted, with which we will measure how many and what key messages caregivers could recall.Based on a preliminary survey in 2013, we estimated that the malaria prevalence was 25% and assumed that the prevalence would be reduced by our intervention by 25%, based on systematic reviews . AssuminThe demographic information of each community in the Ketu South district was compiled by the health directorate through reports by CHNs in each CHPS zone prior to the baseline survey. The total number of communities under the nine selected CHPS zones in the Ketu South district was 57, and we applied the probability-proportionate-to-size method to select 40 communities See Fig. . We exclForty communities were assigned into 8 strata on the basis of the prevalence of diarrhea and economic status, based on the results of the first-round survey. To evaluate the socioeconomic status of a community, we used the proportion of households with wattle and daub houses as representatives of the lowest economic level. We ensured that an equal number of communities within all 8 strata were randomly allocated into the intervention and control arms, with each arm including 20 communities. Microsoft Excel version 15.22 was used for randomization. We ensured comparability in the main outcomes between the intervention and control arms by strictly applying randomization. After conducting the first-round survey, we classified the clusters into strata by primary endpoint and socioeconomic status. In doing so, we were able to ensure a high comparability, and therefore were able to avoid selection bias. Control communities are allocated by randomization among the target communities. We found control and intervention communities well balanced in terms of caregivers’ demographic and socioeconomic status, and child demographic status and several key variables related to primary outcomes of the intervention  coordinated the selection process.The training curriculum for CHVs will be developed in reference to CHV’s training manual , as recoA backpack, t-shirts, an identification card, a CHV certification, a digital thermometer, and stationery will be provided to CHVs. Health equipment such as ORS packets, zinc tablets, and RDT kits will be dispensed in a timely manner to assist their activities. Limited material incentives of 8.7 USD (30 CHC) worth of food items and 1.5 USD (5 GHC) worth of airtime will be also provided every month. The first phase, in which CHVs will be deployed in the 20 treatment communities, will last for 1 year.We referred to the suggested roles in the latest CHPS implementation guidelines (draft version) and the recommended training manual for CHV training  in orderIt is critical for this trial to ensure that CHVs are properly activated in the intervention communities. The key indicators for measuring the activation level of CHVs are the frequency of their home visits, their participation in the monthly meetings, and their retention rate Table .Table 4IThe Improving Maternal and Child Healthcare project in Volta Region of Ghana is being conducted in the Keta, Ketu South and Ketu North districts from January 2014 to December 2016. The three project districts have a total of 24 CHPS facilities within 132 CHPS zones, with a population of 461,939, covering 92,387 children under the age of 5 years. This project aims to enhance the accessibility, availability, and quality of the health services for mothers and under-5 children. In order to accomplish this goal, it provides equipment to health facilities, deploy and activate CHVs, and promotes public awareness.The project is funded by the Korea International Cooperation Agency and implemented by a consortium of the Graduate School of Public Health, Yonsei University and the Korea International Development Institute.Intention-to-treat analysis will be conducted to explore the effect of CHV activation on childhood infectious disease of under-five children. For diarrheal prevalence as a dependent variable, water quantity and quality, hygiene behavior of caregivers, presence of improved latrines, characteristics of the enrolled child such as age and sex, household income, and caregiver’s education level will be controlled for in quantifying the net effect of CHVs. For malaria prevalence as a dependent variable, the enrolled child’s characteristics, household income, and caregivers’ education level will be controlled. Environmental risk factors such as seasonality and altitude are also considered to be independent variables for malaria prevalence. However, the intervention and control arms in our study site present no difference in those factors so there will be no control for environmental factors. When quantifying the net effect of CHVs on child malaria prevalence, insecticide-treated bed net utilization will not be controlled since it is considered an intermediate factor between intervention and disease outcome. Generalized estimating equations will be used for investigation at the cluster level. The random effects model will be used, taking account of between-cluster variation by assuming that there are cluster-level effects. Per-protocol analysis will be performed to obtain additional background information if the overall percentage of CHVs activated does not reach 80%. Multi-level analysis will also be conducted to explore whether the effects of CHVs on child diarrheal and malaria prevalence vary by community depending on a community’s overall coverage of activated CHVs.This study seeks to assess the effects of CHVs on the health gains of children under 5 years of age. We thus rigorously applied a randomization process after calculating adequate cluster and household sample sizes.In this study, we place an emphasis on the preventive role of CHVs in child health. The role of CHVs is to provide education about hand-washing, breastfeeding, the utilization of insecticide-treated nets, ORS treatment and rapid malaria tests, as well as making referrals for sick children to health facilities. We expect the health education using key messages during home visit will facilitate their function for disease prevention. Considering the context of resource-poor settings, the public health implications of the preventive role of CHVs are not trivial.Previous studies did not describe the nature of CHV training or the availability of further education after the initial course. In this trial, CHVs are trained 1 week at the start of the project and regular training will be provided on a monthly basis by CHOs and CHNs.We performed a pre- and post-test right before and after the CHV training. If we found a CHV not achieving a score of 80 out of 100, we retrained him or her. To standardize the regular training, standard operating procedure on the implementation of monthly meetings (Additional file The intervention is not restricted to health education. According to the operational definition of this trial, the key intervention is to help CHVs perform their duties, which mainly involve visiting at least 20 households each month to deliver key messages and provide basic health services established by the policy such as malaria diagnosis and ORS provision.Through in-depth discussion with government officials and community leaders during project design, we realized that merely educating CHVs was not sufficient to help them perform their tasks. We thus developed active supervision and support from government officials such as CHPS in close collaboration with DHMT. By employing a phase-in design for the trial, the government made an agreement that CHV activation would be delayed in the control arm during the first phase since it could be carried out during the second phase. In this regard, we believe that contamination will not take place severely.No monetary subsidies will be provided to CHVs during the trial to strictly comply with the policy of the Ghanaian government, according to which CHVs function as a bridge between community members and CHNs “without affecting the national wage bill,” and rely on the discretion of community members.One of the strengths of this trial is that a process evaluation will be conducted in parallel with the impact evaluation. Few studies have investigated the impact of CHWs using process indicators. In this study, we will use process indicators at each stage to assess reliability, services delivered, services received, participation, recruitment, retention and quality. A range of data will be collected and analyzed to evaluate each process: the appropriateness of selection of CHVs, the quality of their training, the frequency of their visits to each household every 2 months, the number of key messages delivered to each household, the number of key messages caregivers can recall, community participation in relation to CHV activities, their retention rate, and changes in preventive and health-seeking behaviors. Implementation of process evaluation will ensure that we explore how the entire health system affects the activation of CHVs in terms of supervision, logistics, incentives, and by what mechanism this occurs (Additional file One of the limitations of this trial is that malaria cases are not being confirmed using laboratory tests. We will measure fever reported by a caregiver as a proxy indicator of malaria prevalence in both arms of the trial. Although RDTs will be used to test for malaria in children with a fever, this will only be the case for households within the intervention arm since the testing will be conducted by CHVs. Despite its seasonal variance, fever, as the primary manifestation of malaria in young children, can be utilized as an indicator of malaria prevalence, although some source has suggested that it must be interpreted with caution .The project team must start recruiting CHVs in control arm during the second phase and also reached an agreement with the local governments to commence CHV activation without any further delay right after the first phase regardless of any pronounced effects on children. If we have to implement CHV activation in the control arm, we cannot maintain two different arms with and without intervention, which means we cannot compare the outcomes of the intervention during this phase. Hence, we ruled out an optimization phase. We thus cannot consider an optimization phase for this trial although we think optimization is important.Due to the absence of demographic data for the study district, we used estimated population figures for each community derived by the officials of the Ghana Health Service. However, during the baseline survey we found discrepancies between the estimated and actual number of households in communities, and these figures were adjusted during the sampling process in some communities. Although a pre-survey listing the households in each community is recommended to enhance the accuracy of household sampling, budgetary constraints prevented us from carrying out such a survey.CHWs are expected to offer quality health services to the population at a reduced cost. To that end, CHWs have been often required to perform extensive duties, such as health extension workers in Ethiopia or CHWs in Kenya , 37. HowAs incased attention has been paid to the role of CHWs in community health systems in low-income settings, the roles, incentives, and training program involved have become increasingly diversified, which hinders a clear assessment of the effects of different types of CHW programs.  This stu