BackgroundSite performance is key to the success of large multicentre randomised trials. A standardised set of clear and accessible summaries of site performance could facilitate the timely identification and resolution of potential problems, minimising their impact.The aim of this study was to identify and agree a core set of key performance metrics for managing multicentre randomised trials.MethodsWe used a mixed methods approach to identify potential metrics and to achieve consensus about the final set, adapting methods that are recommended by the COMET Initiative for developing core outcome sets in health care.We used performance metrics identified from our systematic search and focus groups to create an online Delphi survey. We invited respondents to score each metric for inclusion in the final core set, over three survey rounds. Metrics scored as critical by ≥70% and unimportant by <15% of respondents were taken forward to a consensus meeting of representatives from key UK-based stakeholders. Participants in the consensus meeting discussed and voted on each metric, using anonymous electronic voting. Metrics with >50% of participants voting for inclusion were retained.ResultsRound 1 of the Delphi survey presented 28 performance metrics, and a further six were added in round 2. Of 294 UK-based stakeholders who registered for the Delphi survey, 211 completed all three rounds.At the consensus meeting, 17 metrics were discussed and voted on: 15 metrics were retained following survey round 3, plus two others that were preferred by consensus meeting participants. Consensus was reached on a final core set of eight performance metrics in three domains: (1) recruitment and retention, (2) data quality and (3) protocol compliance. A simple tool for visual reporting of the metrics is available from the Nottingham Clinical Trials Unit website.ConclusionsWe have established a core set of metrics for measuring the performance of sites in multicentre randomised trials. These metrics could improve trial conduct by enabling researchers to identify and address problems before trials are adversely affected. Future work could evaluate the effectiveness of using the metrics and reporting tool.Electronic supplementary materialThe online version of this article (10.1186/s13063-018-2940-9) contains supplementary material, which is available to authorized users.

BackgroundLarge multicentre trials are complex and expensive projects. A key factor for their successful planning and delivery is how well sites meet their targets in recruiting and retaining participants, and in collecting high-quality, complete data in a timely manner. Collecting and monitoring easily accessible data relevant to performance of sites has the potential to improve trial management efficiency. The aim of this systematic review was to identify metrics that have either been proposed or used for monitoring site performance in multicentre trials.MethodsWe searched the Cochrane Library, five biomedical bibliographic databases (CINAHL, EMBASE, Medline, PsychINFO and SCOPUS) and Google Scholar for studies describing ways of monitoring or measuring individual site performance in multicentre randomised trials. Records identified were screened for eligibility. For included studies, data on study content were extracted independently by two reviewers, and disagreements resolved by discussion.ResultsAfter removing duplicate citations, we identified 3188 records. Of these, 21 were eligible for inclusion and yielded 117 performance metrics. The median number of metrics reported per paper was 8, range 1–16. Metrics broadly fell into six categories: site potential; recruitment; retention; data collection; trial conduct and trial safety.ConclusionsThis review identifies a list of metrics to monitor site performance within multicentre randomised trials. Those that would be easy to collect, and for which monitoring might trigger actions to mitigate problems at site level, merit further evaluation.