Fall rates and fall-related injuries among community-dwelling older adults (≥65 years) are expected to increase rapidly, due to the aging population worldwide. Fall prevention programs (FPPs), consisting of strength and balance exercises, have been proven effective in reducing fall rates among older adults. However, these FPPs have not reached their full potential as most programs are under-enrolled. Therefore, this study aims to identify promising strategies that promote participation in FPPs among community-dwelling older adults.n = 12) at risk of falling. Interviews were audio-recorded, transcribed, and analyzed following a qualitative thematic methodology, with a hybrid approach.This is an exploratory qualitative study. Previously, barriers and facilitators for participation in FPPs by older adults had been identified. Next, six strategies had been designed using the Intervention Mapping approach: (1) reframing; (2) informing about benefits; (3) raising awareness of risks; (4) involving social environment; (5) offering tailored intervention; (6) arranging practicalities. Strategies were validated during semi-structured interviews with community-dwelling older adults  reframing ‘aging’ and ‘fall prevention’: respondents preferred to be approached differently, taking a ‘life course’ perspective about falls, and avoiding confronting words; and (2) ‘informing about benefits’ ; which was mentioned to improve the understanding of the relevance of participating in FPPs. Other strategies were considered important to take into account too, but opinions varied more strongly.This study provides insight into potential strategies to stimulate older adults to participate in FPPs. Results suggest that reframing ‘aging’ and ‘fall prevention’ may facilitate the dialogue about fall prevention, by communicating differently about the topic, for example ‘staying fit and healthy’, while focusing on the benefits of participating in FPPs. Gaining insight into the strategies’ effectiveness and working mechanisms is an area for future research. This could lead to practical recommendations and help professionals to enhance older adults’ participation in FPPs. Currently, the strategies are further developed to be applied and evaluated for effectiveness in multiple field labs in a central Dutch region (Utrecht). It hIn general, physical activity has been related to numerous physical and mental health benefits and well-being, such as the decreased risk of developing stroke, lower blood pressure, and lower risk of cognitive decline and all-cause mortality , 8. SeveDespite that FPPs have been proven to be successful in research settings, their effectiveness in practice is limited due to significant levels of non-engagement and-adherence, and the reluctance of many older people to participate, leading to low uptake rates , 14. In 2.2.1.This is an exploratory qualitative study on the perceptions of community-dwelling older adults on potential strategies that had been designed to promote participation in FPPs. It is part of a Dutch implementation research project: Fall pRevention ImplEmentatioN stuDy (FRIEND), which received ethical clearance from the Ethical Committee Research Healthcare Domain of the HU University of Applied Sciences, Utrecht, Netherlands (113–000-2020). To contribute to explicit and comprehensive reporting of qualitative studies, we completed the Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist  .2.2.In previous studies of the FRIEND project, we identified barriers and facilitators for participation in FPPs by older adults. This was achieved by a quick literature scan, complemented with semi-structured interviews among community-dwelling older adults aged 65 years and older at risk of falling . Next, b2.3.Respondents were selected based on convenience sampling within four districts in the region of Utrecht, Netherlands. We recruited respondents in two ways. Physical therapists involved in the FRIEND-project were asked to inquire whether their patients who met the inclusion criteria and would be interested in participating in a research interview. If they were, their contact information was sent to a researcher (MS) with the consent of the potential respondents. Also, we asked a community center to spread a study flyer among their older members. Those interested could contact the researchers by sending an e-mail with contact details. After receiving contact details, the potential respondents were called by a researcher (MS) to check whether they met the inclusion criteria. During this telephone call, no other personal information than necessary to verify eligibility was shared to prevent possible assumptions about participation in the study, relationship establishment, or other biases.Respondents were included when they were: (1) aged 65 years and older and (2) at increased risk of falling. These criteria reflect the target group of FPPs. Increased fall risk was identified using two questions: “Have you had a fall in the past 12 months?” and “Do you experience difficulties in balance, mobility, or gait?.” Answering “yes” to at least one question indicated an increased risk of falling. This is in accordance with Dutch guidelines for fall risk screening . Respond2.4.Four female researchers  held single-time semi-structured interviews by telephone between December 2020 and March 2021. The interviews were conducted during a COVID-19 lockdown. Therefore, the respondents and researchers were both at home while conducting the interviews. At the time of the study, two researchers (LV and LD) were also involved in educational courses as lecturers. One researcher (MS) was involved in various (inter)national research projects in the health care domain. Another researcher (JB) had a profession as a senior advisor/project leader at a Dutch Centre of Expertise on Health Disparities (Pharos) and as a board member of the European Network of Intercultural Older Adult Care.Three of the four researchers were experienced in conducting qualitative semi-structured interviews, the other researcher was new to this method. To ensure that interviews were performed similarly, the researchers met regularly to discuss how the interviews went to exchange suggestions for improvement. The interviews lasted approximately 60 minutes and were audio-recorded on an offline telephone. Afterward, the recordings were transferred to a secure online research database. No field notes were made.The interview guide was developed iteratively by five researchers . The final interview guide consisted of three parts. The questions in the interview guide were not shared with respondents to prevent bias.First, the respondent and researcher were introduced and the research project was briefly described, after which informed consent was obtained. All respondents provided oral informed consent to proceed with the interview. Also, there was time for the respondent to ask questions, if necessary. Then, general interests were discussed, and demographic characteristics were collected . This part was deliberately positioned at the beginning of the interview, to build rapport between the researcher and respondent.The second part was about the respondents’ view on their neighborhood, in terms of how they moved around in their neighborhood, which local facilities they used , where they met other people, and which type of health care professionals they visited. We decided to insert this part to gain insight into the neighborhood from the perspective of older adults and to identify specific leads on how and where to apply certain strategies. For example, when we know at what types of locations older adults meet each other, we can recommend organizing FPPs at these locations or spreading information through those particular organizations.In the third part, the six previously designed strategies were presented in an informal manner to be understandable for the respondents. For example, to discuss the strategy ‘reframing’, we asked respondents which words they would choose in information material about FPPs aimed at people of similar age. Also, strategies were validated by asking whether a given strategy was important to consider to stimulate participation in FPPs.The final version of the interview guide had open-ended questions and was tested by one of the researchers (MS) in a semi-structured interview with one person from the target group who met the inclusion criteria. At the end of the interview, feedback was collected on the clarity of the questions and the difficulty of answering the questions. During meetings among the researchers, the respondents’ feedback and the experiences of the researcher were discussed, which led to minor changes in the questions in the interview guide. Data from this interview was not included in the data analysis.2.5.The audio recordings of the interviews were transcribed verbatim. Transcripts and finalized findings were not returned to respondents. Four researchers were involved in the data analysis , for which ATLAS.ti Windows Version 22.2.4.0) was used , a coding scheme with predetermined codes based on the topics and sub-topics of the interview guide was created. The coding scheme was used for the deductive part of the analysis, and structured the coding process, ensuring that the researchers executed the coding similarly. This deductive approach enabled us to identify any leads about their neighborhood and allowed for analysis of respondents’ opinions and thoughts on the six presented strategies. The inductive analysis method implied that seemingly relevant text fragments that did not fit the scheme, were coded as ‘other’.The hybrid qualitative thematic analysis comprised several stages . During axial coding), two researchers (MS and LV) summarized the codes of the part ‘view of the neighborhood’ . Then, per strategy, two researchers (MS and LV) reviewed the codes that were derived deductively from the data, for example, specific words the respondents preferred to use in information about FPPs. Also, codes on whether the respondent thought that the strategies were indeed important to stimulate older adults to participate in an FPP were summarized. This enabled us to validate the presented strategies.Next, at the second stage  performed an inductive analysis of the data. This was done by identifying remarkable codes within each of the six presented strategies and the ‘other’ codes, by answering the question: what stands out? An overview of remarkable codes was created per strategy and for the ‘other’ codes. Afterward, connections between the remarkable codes were drawn to draft themes.categorization), the researchers  discussed whether emerged themes could be linked to one of the six presented strategies. The categorization was final when the researchers reached consensus. This resulted in ‘strategy-dependent themes’. When themes did not fit into one strategy but emerged within multiple strategies, we categorized them as ‘strategy-independent themes’.Then, during the third stage . All respondents at least finished secondary school, and 5 of them attained a higher professional education level or university level (The mean age was 77 years (range 65–86). Eleven respondents were female. Almost all respondents lived alone . Then, strategy-independent themes that emerged are described . Results3.3.1.3.3.1.1.Several respondents deemed this as an important strategy. They experienced words such as ‘older adult’ or ‘seniors’ as narrow-minded terms that promote segregation. Respondents mentioned that such words should be avoided and they were asked specifically which terminology they would prefer instead. Recurring answers included words that objectively addresses the target group, such as ‘aged 65 years and older’. Some respondents mentioned that they did not have a preference for wording.Male, 81 years:“‘Seniors’ or ‘older adult’ … there you go stigmatizing people again. There are many people over 80 years of age who are really seniors, and are really old. And there are also people over 80 years of age who are still quite vital and don't feel addressed by ‘seniors’. […] ‘Over-65s’, for example, that's a little bit more neutral.”3.3.1.1.1.One of the major themes that arose from the data within this strategy was that ‘fall’ and ‘fall prevention’ were perceived as stigmatizing topics. Talking about ‘fall prevention’ using these words was unpleasant for almost all respondents. ‘Falling’ was felt to correlate with being old and frail, and as respondents often did not see themselves as being old or at increased risk of falling, they did not recognize fall prevention as relevant to them. However, they felt that they were being stereotyped by others as such.Male, 81 years:“To start talking about 'fall prevention'… I think that also puts a stigma on ‘falling’ because people say: “I don't fall”, but they do fall of course.”As an alternative framing, some respondents suggested a ‘life course perspective’ on falling, since falls occur throughout the life span, and not only at an older age.Female, 69 years:“But shouldn’t we talk about falls befóre 65 years of age. I fell in the house, down the stairs, when I was 46 years. So anyone can always fall; you only need one unguarded moment.”3.3.1.2.This strategy was perceived as important by some respondents; they mentioned that a positive message would likely be appealing and stimulating. Respondents exemplified the type of benefits that could be described, such as ‘living independently for a longer period of time’, or ‘staying fit and healthy’. Also, they talked about the possibility to share these positive messages through stories of peers, for example in magazines.Female, 81 years:“That you can approach it from a positive angle, and not mention disadvantages. The advantages should be more on the foreground, in my opinion. And that it gives you the chance to live independently for longer. I think that's the most important thing.”Male, 81 years:“I notice that the whole prevention circus… that's not a priority. They [older adults] want to be able to focus their lives on other things.”In addition, informing about the benefits of participating in FPPs can be appealing to those who do not feel that falling and fall prevention concerns them. Communicating about matters that are relevant to them, such as being able to walk safely outside, or being active and fit, can increase the potential to reach a large proportion of the older population at risk of falling.3.3.1.2.1.Some respondents emphasized that a positive tone should not be overdone, as this would jeopardize the credibility of the message. Overly positive messages can mismatch people’s expectations of life at this later stage.Male, 82 years:“The idea that you can prevent everything… You really shouldn't hint at that too much, because I don't think any older person believes that. Besides, that conjures up an image that for all older people there would be this kind of perspective, well, that's the utmost nonsense.”Another remark given on informing about the benefits of fall prevention was, that older adults should not be patronized.Male, 82 years:“Within that […] approach, you shouldn’t go too quickly in the direction of ‘that would be good for you’, because we know it ourselves. You shouldn’t, just shouldn’t do that.”A last theme that emerged when discussing this strategy, was that some respondents lacked information, or had incorrect beliefs about FPPs. For example, one respondent thought that participants of an FPP just practiced the act of falling, which she considered risky at an older age. These beliefs can hamper participation. Providing the right information is therefore important and individual preferences should be taken into account.Female, 81 years:“Well, look, a course about ‘learning to fall’… I’m not in favor of that. Because you can fall wrongly at some point anyway. I mean, you can say ‘I’m learning how to fall’, but you would do that when you are 20 or 25 [years old], not when you are 60 or 70.”However, not all respondents felt that informing about benefits would indeed stimulate older adults to participate in FPPs. Specifically, improving fitness and health was mentioned to be less appealing to those who already feel fit and healthy.3.3.1.3.Some respondents mentioned that it was important to inform older adults about risk factors for falling and to emphasize the negative consequences of falls for health and wellbeing. One respondent explicitly mentioned that by raising awareness of risks, people might get warned that they have a risk of falling and what they can do to prevent a fall. It was not expected that this strategy would lead to participation in FPPs directly, but might stimulate cautious behavior.Female, 77 years:“Mentioning why older adults end up in a hospital after a fall, what reasons there are for falling and why it is important to pay attention […]. There are, of course, many people with fractures and I think it is very important to mention this. ‘Watch out, there is a doorstep; watch out, you’re turning too fast or you’re not paying attention to what you are doing, which may cause you to fall’.”3.3.1.3.1.Respondents thought that within this strategy, scaremongering could lead to negative health behaviors. One respondent gave an example of a peer who did not go out of the house at all to prevent a fall. Also, some respondents indicated that part of the older population is not interested in this topic, and therefore, this strategy would probably not affect them.Male, 82 years:“You shouldn’t scare-monger either. […]. I once had a good friend, who did allow herself to get affected by scare-mongering. She did not come out of the house at all, for the purpose of ‘prevention’.”Female, 76 years:“When you do not experience any problems, than you’re probably not very open to the topic. If you don’t know anything about it, than you’re not very interested.”3.3.1.4.Respondents mentioned that to reach the older population, it is important to promote FPPs through the social environment. More particularly, community-based social places (for leisure activity) where peers already get together, was mentioned to be a helpful way to get in contact with older adults. Some respondents indicated that these places were stimulating to start up the conversation about falls and fall prevention. Also, word of mouth in the social environment was considered to be helpful for older adults to motivate each other to participate in FPPs.Female, 77 years:“The social environment is of great importance, because that's the best source to get contact. And that the social contacts are cheering each other on, so to speak, to participate in something.”Male, 81 years:“Especially the use of the social environment, of support from the environment [is important]. It could be a possibility to organize something in the neighborhood that invites residents to talk to each other, so that it really becomes a bit more of a topic of conversation as well, this ‘falling’ and ‘fall prevention’."Additionally, some respondents mentioned that it could be helpful to organize a local activity, such as a theatre show or a market, with a demonstration of what an FPP entails, and where people can try different elements of FPPs .Female, 65 years:“And if the GP and other professionals involved would organize a ‘happening’ twice a year, a market for example. And that they make sure they physically challenge them, resulting in them falling or nearly falling. Or that we have to crawl underneath something… That would be appealing for me.”Female, 77 years:“A theatre performance seems like a great idea. I think there will be quite an interest in that. That you can show, in a very fun way, what is serious about falls, and what are the consequences of falls, but you can put that in a fun setting. I would like it very much.”3.3.1.4.1.Respondents mentioned that offering FPPs in addition to already existing physical activities in the neighborhood, such as gym classes, might help to stimulate older people to participate in FPPs.Female, 77 years:"I am sure that if they had offered it at our gym club, I definitely would have participated.”3.3.1.5.Respondents felt that this strategy was important to consider when stimulating older adults to participate in FPPs: professionals providing FPPs should take into account that every individual has different interests and needs to which the intervention should be tailored.Female, 85 years:“I think it is very important. They (older adults) are all different, of course. You have to take everyone into account separately. One person can't do this and the other can't do that. One can't ride a bike and the other can't do that. You should have to take that into account a little bit.”3.3.1.6.Female, 77 years:“As it starts costing money, and a lot of money, then there is no chance people will participate. On the basis of this problem, I would like to address to the insurance companies that they must do something about it.”Female, 65 years:“I think especially the location, so that it is central in a neighborhood […]. Maybe you should also offer it at multiple locations then."Some respondents recognized the importance of this strategy. In particular, some respondents indicated that making sure that the costs associated with an FPP were covered , would enhance their motivation to participate. Furthermore, organizing an FPP at an accessible location seemed to be essential. The location should be centrally located in the neighborhood so that it is nearby and available for all people.Besides location, the time of day was mentioned as an important practicality. Some respondents mentioned that people in the target group may have busy schedules, for example, because of babysitting their grandchildren or social activities. However, individual differences were found to be large, making it challenging to find the right time slot.Female, 75 years:“I think you have to give people a choice, because there are people who want it [an FPP] very early in the morning and other people want it a little later in the day. That's also very personal. So I suppose, if there are multiple times that it is organized in a day, that you have a choice. That seems important to me.”3.3.2.Other strategies that emerged from the data were (a) humor and (b) personal approach.a) Humor: humor was expected to be helpful in communicating about FPPs with older adults. Respondents assumed that humor would facilitate knowledge uptake, and decrease perceived barriers to talking about the unpleasant topic of falling.Female, 69 years:“What also works here, I think, is laughter. There is no education as strong when it is intertwined with laughter. You absorb an awful lot of knowledge when you laugh.”b) Personal approach: respondents mentioned that it is important to have an actual person, preferably a health or social care professional, who initiates the contact about fall prevention, as this would stimulate them to participate in FPPs. Additionally, posters or flyers could be distributed to start the conversation about fall prevention. Whether this would also stimulate the intention to participate remained uncertain.Male, 81 years“I can be brief about that [what the most appropriate channel is]: that has to be trough a personal approach. Because with flyers; you pick them up and then you take a look at them, but the chance that it leads to further actions is - in my case - not great. […]. I never believe that a flyer is able to get people willing to join a fall prevention course or something like that […]. Maybe it may have its use when such a flyer has been lying around for a while and they have taken it and someone comes to ask them about it, and than it is something familiar. But it won’t be enough."4.Although there is an extensive and growing body of evidence that supports the effectiveness of FPPs to reduce fall rates in the older population , 12, parOne of the most prominent themes that emerged from the data within the strategy ‘reframing’ was that ‘old’, ‘falling’, and ‘fall prevention’ are stigmatized topics, from which older adults prefer to dissociate themselves. This leads to respondents not recognizing themselves as being ‘old’ or a ‘faller’ and therefore a lack of urge to participate in FPPs. This implies that reframing is an important strategy to promote participation in FPPs. Research has shown that older adults experience ‘falling’ as a symbol of being disabled, loss of independence, and frailty , 15, 27.Moreover, informing older adults on the perceived benefits of participating in FPPs could be appealing and stimulating for them, when framed positively and without mentioning it is about a program focusing on ‘fall prevention’. Many older adults do not see themselves participating in FPPs, as this relates to being ‘old’ and a ‘faller’, but do find it important to stay fit and healthy, to be able to live independently at home for as long as possible, and in good health. Therefore, older adults may be more willing to participate in exercise programs that emphasize the benefits of FPPs, such as helping to stay fit and healthy and being able to keep performing hobbies and other activities that are important to them , 29.The importance of positively framed communications about falls (prevention) and age has been highlighted in many other studies as well , 29, 30.Furthermore, the importance of social support was validated by respondents in the current study. In particular, our respondents thought that an FPP provided by a sports club or other community-based center they already visited, would be easier to participate in. The places they mentioned were mainly churches, community centers, and group activities in residential settings. Also, respondents in this study mentioned that peers might encourage each other by discussing the topic. Previous research has also shown that social influences from families, peers, and health care professionals in the community are essential in stimulating older adults to participate in exercises or fall prevention , 35. SpeIn addition, personal preferences between individuals vary greatly, and this has to be taken into account as well. Respondents in the current study thought that personalizing the intervention to their needs and wishes was important, making FPPs more appealing. Other studies have shown great variation in personal factors  that influence adherence to exercise programs in older adults , 36. ThiIn addition, in the current study, respondents also expressed the importance of addressing practical issues of an FPP. Especially, providers should ensure that the location of the FPP is easily accessible. Moreover, costs were experienced as a major barrier, and therefore compensation through, for example, health insurance should be considered. Such program factors  have been shown to influence older adults’ adherence rates to exercise programs in previous studies as well , 36, 37.Interestingly, two themes  emerged from the data during the discussion of multiple strategies (strategy-independent themes). The theme ‘personal approach’ emerged from the data, as respondents mentioned that information about fall prevention could be spread through different channels. Some preferred to be informed about fall prevention by professionals in the field. Results showed that the physical therapist and general practitioner were among the mostly visited health care professionals; they play an essential role in bringing up ‘fall prevention’. Additionally, flyers, posters, and advertisements could help to start the conversation about fall prevention. Previous research on recruitment strategies concluded that, for recruiting participants in research including physical exercise interventions, advertisement in local newspapers was the most effective method. Mass media or billboards were less effective, whereas interpersonal contact such as word of mouth was a more successful strategy for recruitment , 39. Fur4.1.A major strength of this study is that we consulted people from the target group themselves. The end-users are the experts in their particular area, and they are the people who need to but often fail to participate in FPPs. Participatory approaches with people who are affected by the decisions to be made, are increasingly recognized to be fundamental and have been shown to impact both the rigor and relevance of research . FurtherThere are also limitations to this study. First, we experienced difficulties in recruiting respondents. Our primary recruitment strategy was to find eligible respondents through health care professionals, but a COVID-19 lockdown with restrictions on interpersonal contacts might have resulted in hesitance to participate in research projects. Additionally, we primarily attempted to recruit a heterogeneous sample , because it is known that such demographic factors are associated with fall rates and participation rates in FPPs , 41. How4.2.Currently, several strategies are further developed to be applied and evaluated for effectiveness in multiple field labs in a central Dutch region within the larger FRIEND project. The main focus of this follow-up research is to examine the effectiveness of one single strategy to improve intention to participate in FPPs among community-dwelling older adults at risk of falling. For this purpose, we chose the strategy that was most extensively discussed during the interviews (reframing), and within which highly remarkable themes derived. We will present two different messages about participating in FPPs to older adults at risk of falling; one with a positively reframed message and one with a neutral message. This may help to gain further insight into the effectiveness and working mechanisms of these strategies and enable us to design practical recommendations within the strategies, which health and social care professionals can apply to improve participation rates in FPPs. Additionally, in this follow-up research, we aim to recruit a large and heterogenous sample, enabling us to include demographic factors in the analyses as well, resulting in more understanding of the effectiveness of the strategy across different subgroups within the older population.Furthermore, benefits from an exercise-based FPP do not only depend on participation and adherence but also the continuation of physical activity afterwards . Communi5.In conclusion, it is crucial to understand which strategies may be effective to improve the low engagement and participation rates of FPPs among community-dwelling older adults at risk of falling. Overall, a personalized approach, informing about benefits, and framed in positive terms, may help promote the participation of FPPs among older adults. Future research should focus on further developing and implementing the strategies that influence older adults’ participation in FPPs. This could result in practical recommendations and help professionals in the community to promote older adults’ participation in FPPs. Next, research should be performed on establishing and implementing referral pathways after participation in an FPP, to retain older adults in regular sports and physical recreation activities in the community, and to improve long-term health benefits.meike.vanscherpenseel@hu.nl.The datasets presented in this article are not readily available because it is a qualitative study; we drew conclusions based on interviews and the transcripts are not available to review due to privacy regulations. Requests to access the datasets should be directed to MS, The studies involving human participants were reviewed and approved by Ethical Committee Research Healthcare Domain of the HU University of Applied Sciences Utrecht, Utrecht, Netherlands (113-000-2020). The patients/participants provided their written informed consent to participate in this study.MS, LV, LD, SV, and AR contributed to the design of the study, and conceptualized the approach for this study. MS, LV, LD, and AR performed the data collection and data analysis. MS wrote the first draft of the manuscript and led the manuscript writing. LV, AR, and SV wrote substantial parts of the final manuscript. LD reviewed the text in detail. All authors contributed to the article and approved the submitted version.Meike van Scherpenseel, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Lidia van Veenendaal, Research group Proactive Care for Older Adult People Living at Home, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands and Bachelor Nursing Studies, Institute for Nursing Studies, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Lennie Donné, Research group Innovation in Healthcare Processes in Pharmacology, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands and Program group Persuasive Communication, department of Communication Science, University of Amsterdam, Amsterdam, Netherlands. Saskia te Velde, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Amber Ronteltap, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Cindy Veenhof, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands and Department of Rehabilitation, Physiotherapy Science and Sport, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands. Marielle Emmelot-Vonk, Department of Geriatrics, University Medical Center Utrecht, Utrecht, Netherlands. Di-Janne Barten, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Nienke Bleijenberg, Research group Proactive Care for Older Adult People Living at Home, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Rixt Zuidema, Research group Proactive Care for Older Adult People Living at Home, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, Netherlands. Elise Volk, Research Group Innovation of Human Movement Care, Research Center for Healthy and Sustainable Living, HU University of Applied Sciences Utrecht, Utrecht, NetherlandsThis research was co-funded by Regieorgaan SIA, part of the Netherlands Organization for Scientific Research (NWO). The funder had no role in the conception and design of this study, data collection, data analysis, interpretation, or the writing of this manuscript (grant number: RAAK.PRO03.099).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


A number of scientific publications and commentaries have suggested that standard preparedness indices such as the Global Health Security Index (GHSI) and Joint External Evaluation (JEE) scores did not predict COVID-19 outcomes. To some, the failure of these metrics to be predictive demonstrates the need for a fundamental reassessment which better aligns preparedness measurement with operational capacities in real-world stress situations, including the points at which coordination structures and decision-making may fail. There are, however, several reasons why these instruments should not be so easily rejected as preparedness measures.From a methodological point of view, these studies use relatively simple outcome measures, mostly based on cumulative numbers of cases and deaths at a fixed point of time. A country’s “success” in dealing with the pandemic is highly multidimensional – both in the health outcomes and type and timing of interventions and policies – is too complex to represent with a single number. In addition, the comparability of mortality data over time and among jurisdictions is questionable due to highly variable completeness and representativeness. Furthermore, the analyses use a cross-sectional design, which is poorly suited for evaluating the impact of interventions, especially for COVID-19.Conceptually, a major reason that current preparedness measures fail to predict pandemic outcomes is that they do not adequately capture variations in the presence of effective political leadership needed to activate and implement existing system, instill confidence in the government’s response; or background levels of interpersonal trust and trust in government institutions and country ability needed to mount fast and adaptable responses. These factors are crucial; capacity alone is insufficient if that capacity is not effectively leveraged. However, preparedness metrics are intended to identify gaps that countries must fill. As important as effective political leadership and trust in institutions, countries cannot be held accountable to one another for having good political leadership or trust in institutions. Therefore, JEE scores, the GHSI, and similar metrics can be useful tools for identifying critical gaps in capacities and capabilities that are necessary but not sufficient for an effective pandemic response. Since the start of the pandemic, a number of scientific publications and commentaries have suggested that scores based on the WHO’s States Party Self-Assessment Annual Reporting tool (SPAR) and the Joint External Evaluation (JEE) tool and the Global Health Security Index (GHSI) did not predict COVID-19 outcomes . Citing But do the analyses comparing mortality to SPAR and JEE scores and the GHSI really prove that these measures are not valid measures of a country’s preparedness , 10? PreFirst, as Stoto and colleagues  note, thSecond, these studies use relatively simple outcome measures, mostly based on cumulative numbers of cases and deaths at the country level and at a fixed point of time. However, a country’s “success” in dealing with the pandemic is highly multidimensional – both in the health outcomes and type and timing of interventions and policies. Performance as measure by cumulative numbers of cases or deaths early in the pandemic might be contradicted by performance in later stages (e.g. when the vaccine became available). Total cases and deaths also do not reflect differences within countries by socio-economic groups, geography, or other factors. In addition, limiting social and economic disruption is an important policy aim that is not addressed by case/death counts. In other words, the impact of capabilities that were highly effective for some groups at a specific time might not be observed in cumulative mortality figures.Third, the analyses to assess predictive validity use cross-sectional designs with outcome data aggregated over multiple epidemic phases, which is poorly suited for evaluating the impact of interventions, especially for COVID-19 policies, where part of the challenge was to adjust policies to the emergence of new variables and new socio-economic impacts over the long course of the pandemic , 14. CroBeyond questions of data quality and study design, there is a serious conceptual issue: a major reason that current preparedness measures fail to predict pandemic outcomes is that they do not adequately capture variations in the presence of effective political leadership needed to activate and implement existing system, instill confidence in the government’s response; or background levels of interpersonal trust and trust in government institutions and country ability needed to mount fast and adaptable responses. As Bell, Fukayama, and others have noted, these factors are crucial; capacity alone is insufficient if that capacity isn’t effectively leveraged , 16. TheLedesma and colleagues  recentlyAs always in assessing measurement systems, the purpose is critical. If the goal is, as suggested by the Independent Panel, to identify “the points at which coordination structures and decision-making may fail” , analysePreparedness metrics, however, were not intended to predict outcomes. Rather, the WHO’s SPAR tool was developed to hold countries accountable for fulfilling their obligations under the International Health Regulations . Other mIt is also important to consider the nature of the systems that we are seeking to measure and improve. Predictive validity is a perfectly reasonable approach in systems where cause-effect relationships are relatively stable and knowable. However, such reliable “if–then” knowledge is harder to come by in highly complex and changing systems, and where the impact of a factor X may be highly conditional on the any number of contextual factors. Prediction would, of course, be very desirable in such situations. Here we are reminded of Berwick’s widely-read essay “The Science of Improvement,” where he argues that for complex social interventions – “whose effectiveness … is sensitive to an array of influences: leadership, changing environments, details of implementation, organizational history, and much more”  – it is


This review focuses on government use of technology to observe, collect, or record potential criminal activity in real-time, as contrasted with “transaction surveillance” that involves government efforts to access already-existing reviews ( The typical urban police department today makes daily use of an array of real-time surveillance tools, ranging from closed-circuit television (CCTV), aerial cameras, and cellphone tracking to automatic license plate readers (ALPRs), facial recognition technology (FRT), and gunshot detection systems. Despite their popularity, the effectiveness of these surveillance technologies in achieving the government’s aims is largely unstudied, as is their empirical validity and reliability. Furthermore, their use has not been subject to the type of constitutional and statutory regulation that has long governed use of other types of real-time surveillance, such as wiretapping and bugging.This article first reviews the small amount of existing research on the efficacy of these surveillance technologies. It then canvasses the extent to which the constitutional law—and, to a lesser extent, statutory and evidentiary law—has or might put strictures on their deployment. The focus of this review is on real-time surveillance, as opposed to the use of computers, algorithms, and other technologies to access and analyze already-collected data.Police use surveillance technologies for a wide variety of purposes, ranging from deterring or intercepting crime to suppressing protest and collecting data for future investigations. Yet we know surprisingly little about the surveillance capacities of police departments nationwide. There is little in the way of a basic descriptive inventory of the surveillance technologies local and federal law enforcement agencies use, and there is even less in the way of peer-reviewed, independent evaluations of the effectiveness or impact of these technologies in terms of crime reduction, accuracy, error rates, equity, or cases cleared by arrest.Methodologically, a key reason for this paucity of information is that these technologies are usually not rolled out in any sort of systematic way, making it difficult to make causal inferences about their impact. More fundamental, however, is that unless one works with law enforcement or the private companies that develop these programs, access to relevant data is limited, which precludes any sort of independent oversight, scientific evaluation, or community input. Owing to the lack of external evaluations, legal scholars and judges rely heavily on company-produced information on their prevalence, use, reliability, and validity, which may overstate the utility of technologies or understate problems or unintended consequences.There are various reasons for the lack of transparency around surveillance technologies. Some of the secrecy is by design—law enforcement does not want to disclose cutting-edge investigative techniques . The polDespite the lack of systematic data, researchers and journalists have begun to open the black box of police departments’ surveillance technologies through qualitative case studies  or stationary  and can capture thousands of plates a minute. Cameras typically capture two photos of every vehicle that passes through their line of vision—one of the car and one of the license plate— and record the location, date, and time the plate was captured. These data then can be linked to and compared with information in other databases, including traffic and toll cameras or “heat lists” of outstanding warrants or stolen cars . Law enfALPRs are becoming increasingly common. According to a recent national survey of law enforcement agencies , almost Despite their spread, the evidence base for the effectiveness of ALPRs is extremely limited. In their review of the research, Whereas ALPRs are dragnet surveillance tools, meaning they collect information on everyone rather than merely those under suspicion, there are also vehicle tracking devices that law enforcement can embed in specific target vehicles. These devices are used to provide remote tracking capability when line-of-sight tracking is not feasible.GPS devices embedded in vehicles have become increasingly common in both small and large police departments, with almost one in four law enforcement agencies reporting some reliance on them. They are relatively cheap and easy to use. Adoption follows a pattern similar to that found with ALPRs; agencies in more urban areas and areas with lower percentages of non-Hispanic Whites are more likely to use vehicle tracking devices than rural areas or those with predominantly non-Hispanic White residents .A 2017 report from the National Institute of Justice suggests the efficacy of using vehicle trackers as a pursuit technology varies widely by department, in part because it depends on how well they are implemented. In May 2015, the Office of Community Oriented Policing Services , a compoAerial surveillance, although more expensive and less common than vehicular surveillance, is a growing modality of law enforcement surveillance. Aerial surveillance can be conducted via plane, helicopter, or unmanned aerial vehicle .As with ALPRs and tracking devices, aerial surveillance can be conducted in real-time or record images for later access.The Center for the Study of the Drone at Bard College found that as of 2020, 559municipal police departments in the United States had acquired drones . The CenThere have been reports of jurisdictions in Illinois, Ohio, and California claiming UAVs helped them more quickly document accidents and reopen roadways, find an escaped inmate , and cleLaw enforcement uses CCTV, also known as video surveillance, primarily to deter crime and record footage for potential future investigations. Today, most cameras are digital, with long-term storage capacity. Cameras can also come with zoom, night-vision, audio, and FRT. Law enforcement agencies have their own CCTV cameras in public places but also may gain access to private cameras through public–private surveillance programs. There have been more systematic studies of CCTV than other surveillance technologies covered in this review. Early studies produced mixed results, but a few studies in the United Kingdom attributed significant drops in particular crimes of between 25% and 56%, although displacement effects were not always taken into account  but more often to obtain data about a person’s past locations in an effort to determine whether they were near the scene of a crime (a practice sometimes known as geofencing).In fact, “Verizon alone received over 13,000 warrants for cellphone location data in the second half of 2020” . AccordiGiven the ubiquity of tracking requests, police departments clearly think tracking is a useful law enforcement technique. There are numerous anecdotal reports that it has aided police in capturing the perpetrators of serious crimes . As withShotSpotter is an acoustic gunshot detection technology. The locators are typically installed at a rate of 20–25 sensors per square mile and primarily connected via 3G and 4G networks (mostly AT&T and Verizon) .In 2020, acoustic locator technology was installed in 110 cities and 12 campuses, covering 779 square miles. As of 2021, ShotSpotter evidence had been used in 190 court cases . The senThe NYU School of Law Policing Project (which receives funding from ShotSpotter) published an evaluation in 2021 that found a significant drop in gun violence in St. Louis, Missouri, after installation of ShotSpotter . HoweverPolice have long relied on ordinary civilians to aid in their surveillance efforts. However, more recently networked technologies and “smart” security devices have intensified this practice of “surveillance deputization” . One such example is Amazon Ring. Ring involves a video doorbell that links with other Wi-Fi-enabled products and integrates with its social media app, called Neighbors.Although precise numbers are unclear, recent reports suggest approximately 2,000 departments are partnered with Ring . All butAn NBC news investigation of 40 law enforcement agencies suggests there is little evidence to support Amazon’s claim that Ring is an effective investigatory tool . ThirteeSeveral new technologies allow law enforcement to “see” through opaque surfaces. For instance, thermal imagers allow police to detect heat signals through walls, trees, or smoke in real-time and can also enhance the night-vision capabilities of the police . ImagersThe key accuracy issue with these devices is determining what a particular image means. A thermal imager’s identification of a significant heat source inside a building could be evidence of a marijuana farm or evidence of a movie studio. Similarly, even if a gun detector is fairly accurate at detecting a gun, all 50 states and the District of Columbia permit citizens to carry concealed weapons under various circumstances. Thus, although such information may improve police situational awareness when they already suspect an individual of criminal activity, there is no evidence of their utility in solving crimes.Classic electronic surveillance consisted of “bugging” a suspect’s phone. Today, wiretapping of phone conversations is supplemented by interception of emails and “envelope” information identifying the sender and receiver of electronic communications (using pen registers and trap and trace devices), and by examination of the content of stored messages and associated subscriber information. Under federal law, the first type of surveillance requires a warrant , and the second and third types of surveillance also require a court order under most circumstances, although not a warrant .The federal government compiles annual statistics about both the frequency and results of electronic surveillance. In 2019–2020, 2,377 wiretaps were authorized, with 1,297 authorized by federal judges and 1,080 authorized by state judges. In 1,503 of these cases, an extension beyond the 30 days of the original order was requested, and all such requests were granted. Most interception orders were focused on mobile phones. As a result of these wiretaps, by December 2020, 6,574 persons had been arrested and 311 persons had been convicted . All theAs with the other technologies discussed here, the effectiveness of electronic communications technology is hard to gauge. One survey of the available anecdotal evidence suggests that “wiretapping is particularly useful in conspiracies such as organized crime and drug cases” and “foreign-intelligence and terrorism cases” , p. 98 bA subset of communications surveillance involves Stingrays, or international mobile subscriber identity (IMSI) catchers. Stingrays essentially operate as fake mobile towers that mimic a wireless carrier cell tower using a stronger signal, which overrides the carrier towers and causes nearby cell phones to connect to them instead. Stingrays can be used to identify and track phones even when they are not making calls or accessing data services. The devices can be mounted in vehicles, airplanes, helicopters, or drones or can be handheld. Typically, law enforcement puts them in cars with compatible computer software . DocumenA 2018 ACLU report shows that at least 26 states are known to have or use Stingrays , p. 8. HUse of surveillance technologies is increasing among law enforcement agencies. On-the-ground qualitative research involving police, technology companies, and community members is required to understand how surveillance technologies are used and their impact on surveilled community members. Unfortunately, these technologies are often rolled out in secret, without community buy-in, and they are rarely deployed in a systematic fashion. As a result, information about prevalence and effectiveness is limited, as this very brief review illustrates. The National Institute of Justice has recognized that “agencies that plan to deploy and evaluate a new technology would benefit from an end-to-end assessment process that includes collecting comparable baseline data” . As manyA welter of statutes and regulations at both the federal and state levels governs the use of the surveillance technologies described above. Although some of these laws will be noted below, the primary focus of this analysis will be the Supreme Court’s Fourth Amendment jurisprudence, which sets forth the minimum legal requirements that surveillance by the government must meet. The Fourth Amendment prohibits unreasonable searches and seizures of “persons, houses, papers and effects” and requires that warrants authorizing a search or seizure be based on probable cause and describe with particularity the place to be searched and the person or things to be seized. The Supreme Court has had difficulty in both determining when surveillance is a “search” or “seizure” and deciding whether, if surveillance triggers Fourth Amendment protection, a warrant is required to make it reasonable. As a result, the Fourth Amendment has had little or no impact on most of the surveillance technologies discussed here. Nor in most cases has either Congress or state legislatures seen fit to regulate such surveillance through statutes.The Fourth Amendment is only implicated by government action that is a search or a seizure. The definition of “search,” the term most relevant to surveillance, has vacillated. The Supreme Court has never defined that word the way a layperson would, as an effort to look at, for, or through something. Rather, in its early cases, the Court determined whether the police action involved physical intrusion into one of the four protected areas listed in the amendment: persons, houses, papers, or effects. Thus, for instance, according to a 1924 Supreme Court decision, police forays onto private property outside the immediate “curtilage” of the home were not searches—even though they involved trespasses—because they did not target the “house” . Nor, thLooking inside a home did not implicate the Constitution either, so long as the observation was from a “lawful vantage point” such as a public sidewalk or an apartment hallway; according to the Court “the eye cannot commit the trespass condemned by the Fourth Amendment” , p. 454.Then, in 1967, the Court decided Yet none of these arguments persuaded a majority of the Court. In holding that the police should have obtained a warrant authorizing the recording, the Court shunted aside the debate over whether a phone booth is a constitutionally protected area. Rather, Justice Stewart’s opinion stated that “the Fourth Amendment protects people, not places” , p. 351.Katz definition of search, this new formulation is narrower than the lay definition of that word. But, given the resolution of the Katz case, the expectations-of-privacy language seemed to contemplate a much broader scope of Fourth Amendment protection than the trespass-oriented language found in earlier Court opinions.The reasonable expectation of privacy language in Justice Harlan’s opinion has since become the primary means of defining when law enforcement engages in a Fourth Amendment “search.” Like the pre-Katz that way. In 1968—one year after Katz and a second Supreme Court decision, Congress certainly read Katz and Title III signaled that some types of surveillance would be subject to heightened scrutiny. Despite Katz’s relatively capacious language, however, for the next half-century the Supreme Court’s caselaw had the effect of confining that decision’s holding to its facts, with the result that surveillance that did not involve interception of communications was left unregulated by the Constitution. This caselaw developed four doctrines—the knowing exposure doctrine, the general public use doctrine, the evidence-only doctrine, and the assumption of risk doctrine—that had the effect of freezing Fourth Amendment law in its pre-Katz state throughout the twentieth century. Only in the past twenty years has the Court, perhaps realizing that its jurisprudence had essentially rendered the Fourth Amendment irrelevant in the digital age, begun to back away from all four doctrines.Katz itself said that although conversations over a public phone can be private for Fourth Amendment purposes, “[w]hat a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection”  without triggering the Fourth Amendment. Less clear is whether innovative surveillance technologies such as drones or facial imaging implicate the Fourth Amendment; given the ubiquity of both drones and facial recognition functions (on cellphones), however, the general public use doctrine may exempt from constitutional regulation those surveillance techniques as well.As with its treatment of the knowing exposure doctrine in Dow Chemical involved surveillance of the outside of business property, Kyllo permits surveillance of the home with technology if that technology is available to the general public. Furthermore, Kyllo states that even sophisticated technology—devices that are not in general public use—can be used to look inside a home if it only detects what a police officer could see with the naked eye from a traditional “lawful vantage point”  cannot prevent the government (the second party) from obtaining personal information that is voluntarily surrendered to another person or entity (the third party), which explains why this rule is also often called the “third-party doctrine.”Miller, in contrast, the third party was a bank. The Court held that even here one assumes the risk of a breach of confidence and, therefore, that depositors cannot reasonably expect that the information they convey to their banks will be protected by the Fourth Amendment. In The most important decision in this regard is Miller and Smith, which came at the dawn of the Information Age, have enormous implications for law enforcement investigation today. The quantity of the world’s recorded data has doubled every year since the mid-1990s  “[t]here is a world of difference between the limited types of personal information addressed in Smith and Miller and the exhaustive chronicle of location information casually collected by wireless carriers today”(b) “[c]ell phone location information is not truly ‘shared’ as one normally understands the term [because] cell phones and the services they provide are. . .indispensable to participation in modern society” . In a separate concurring opinion, Justice Sotomayor, while joining the majority’s trespass reasoning, likewise expressed concern about the “aggregated” data that tracking devices allow .As the dissent in It is also important to recognize, however, that a conclusion that use of a surveillance technology is a search does not end the analysis. “Reasonable” searches are still permissible. That is the second question the Fourth Amendment poses.Jones, Kyllo, Jardines, and Carpenter, the Supreme Court indicated that a warrant was required to authorize the police action . Likewise, in Leaders of a Beautiful Struggle, the Fourth Circuit held that a warrant was required for aerial surveillance. It is important to recognize, however, that there is a difference between the first four cases and the last one. In each of the Supreme Court’s cases, the police could have obtained a warrant, at least in theory, because police had an identified suspect. In Leaders, in contrast, a warrant would have been impossible to obtain—probable cause obviously could not be demonstrated for every person subject to surveillance, and even after a crime occurred, probable cause to track a particular “dot” could not be made out unless, perhaps, there was only one dot at the crime scene.Typically, a search is reasonable if it is authorized by a warrant based on probable cause. In Leaders, the reasonableness of a program  is at issue, “an adequate substitute for a warrant” may suffice. This language comes from the Court’s decision in The Supreme Court’s cases suggest that when, as in Requires inspection of all mines and specifically defines the frequency of inspection. . . .[T]he standards with which a mine operator is required to comply are all specifically set forth in the [Mine Safety] Act or in. . .the Code of Federal Regulations. . . .[R]ather than leaving the frequency and purpose of inspections to the unchecked discretion of Government officers, the [program] establishes a predictable and guided federal regulatory presence  only regulate actions of the government, not of private individuals. In upcoming years, the scope of the state action requirement may be the most important legal issue with respect to surveillance. Today, private companies, many of them data brokers, have acquired mountains of information about each of us and are willing to monetize it—indeed, they may be set up with that goal in mind , with soThe Supreme Court has found state action not only when government directs a private party to conduct a search but also when there are “clear indices of the Government’s encouragement, endorsement and participation” (If, in light of these realities, it were concluded that routine government use of a given company’s surveillance information constitutes state action, the implications could be significant. It would require not only that, before acquiring information from such companies, the government have the requisite justification for accessing the type of information it wants but also that the data collection or surveillance by the company meets the same legislative authorization and data security and retention requirements that Fourth Amendment doctrine imposes on government-run programs.Despite their ubiquity, the empirical evidence base for surveillance technologies is weak. For most technologies, even basic information about how many departments use them or how they are deployed is lacking. Even less accessible is good information about surveillance technology’s financial and privacy costs, its impact on police–community relations, and its value in detecting and deterring crime.Although there is relative consensus regarding the lack of empirical data on many surveillance technologies, there is a distinct lack of consensus about what to do about it. Whereas reformist approaches tend to focus on using existing constitutional, statutory, and evidentiary frameworks to regulate the police, abolitionists argue that even well-intentioned reform efforts have the ultimate effect of legitimizing and entrenching the carceral system and creating new pathways for introducing surveillance technologies in other jurisdictions and contexts. Scholars, activists, policymakers, and lawyers have variously argued that given some combination of the lack of evidence about the effectiveness of these technologies, their intrusiveness, and the possibility that they will have an unfairly disparate impact on minority communities, they should be banned altogether or at least significantly circumscribed, through either executive action, legislative direction, or constitutional litigation.To date, the courts and most legislatures have avoided this debate. At the same time, the courts have begun to recognize the extent to which technology has enhanced police ability to conduct surveillance. Increasingly, they appear willing to interpret Fourth Amendment search doctrine to encompass new pervasive surveillance techniques and perhaps even to regulate those techniques that are primarily instigated by private parties. The Fourth Amendment is most likely to require a warrant when surveillance technologies are used to observe activities inside the home, access the contents of communications and cellphones, and track public activities over a long period of time. If instead government uses technology to collect information for later access, courts are more likely to defer to statutory and administrative regulation of the data collection and its retention . As tech