The PRECIS-2 tool has good interrater reliability and modest discriminant validity.
OBJECTIVES
PRagmatic Explanatory Continuum Indicator Summary (PRECIS)-2 is a tool that could improve design insight for trialists. Our aim was to validate the PRECIS-2 tool, unlike its predecessor, testing the discriminant validity and interrater reliability.


STUDY DESIGN AND SETTING
Over 80 international trialists, methodologists, clinicians, and policymakers created PRECIS-2 helping to ensure face validity and content validity. The interrater reliability of PRECIS-2 was measured using 19 experienced trialists who used PRECIS-2 to score a diverse sample of 15 randomized controlled trial protocols. Discriminant validity was tested with two raters to independently determine if the trial protocols were more pragmatic or more explanatory, with scores from the 19 raters for the 15 trials as predictors of pragmatism.


RESULTS
Interrater reliability was generally good, with seven of nine domains having an intraclass correlation coefficient over 0.65. Flexibility (adherence) and recruitment had wide confidence intervals, but raters found these difficult to rate and wanted more information. Each of the nine PRECIS-2 domains could be used to differentiate between trials taking more pragmatic or more explanatory approaches with better than chance discrimination for all domains.


CONCLUSION
We have assessed the validity and reliability of PRECIS-2. An elaboration study and web site provide guidance to help future users of the tool which is continuing to be tested by trial teams, systematic reviewers, and funders.
['Loudon|Kirsty|K|', 'Zwarenstein|Merrick|M|', 'Sullivan|Frank M|FM|', 'Donnan|Peter T|PT|', 'Gágyor|Ildikó|I|', 'Hobbelen|Hans J S M|HJSM|', 'Althabe|Fernando|F|', 'Krishnan|Jerry A|JA|', 'Treweek|Shaun|S|']
D006801:Humans D015588:Observer Variation D016032:Randomized Controlled Trials as Topic D015203:Reproducibility of Results D012107:Research Design
Face validity Randomized controlled trials Validity and reliability Clinical trial methodology Pragmatic clinical trial Trial design