Elfeky A, Treweek S, Hannes K, et al. Using qualitative methods in pilot and feasibility trials to inform recruitment and retention processes in full-scale randomised trials: a qualitative evidence synthesis. BMJ Open 2022;12:e055521. doi: 10.1136/bmjopen-2021-055521

It has been brought to our attention that we attributed data included in our synthesis to a summary paper (Audrey S. Qualitative research in evidence-based medicine: improving decision-making and participation in randomised controlled trials of cancer treatments. Palliat Med 2011;25:758–65) rather than to the original data source used by Audrey (Donovan, F. Hamdy, D. Neal, T. Peters, S. Oliver, L. Brindle, D. Jewell, P. Powell, D. Gillatt, D. Dedman, N. Mills, M. Smith, S. Noble, A. Lane and T. S. G. Protect. Prostate Testing for Cancer and Treatment (ProtecT) feasibility study. Health Technology Assessment (Winchester, England). 2003; 7 (14): 1–88)). The former is a commentary article on the findings from the Donovan et al 2003 paper. In addition, we have also identified that a further study (Stein RC, Dunn JA, Bartlett JMS, Campbell AF, Marshall A, Hall P, et al. OPTIMA prelim: a randomised feasibility study of personalised care in the treatment of women with early breast cancer. Health Technol Assess 2016;20(10).) was also omitted.

Both the Donovan et al 2003 and Stein et al 2016 studies were identified in the original search but through human error were not taken forward for full text assessment. Our investigation of this error also highlighted that the reference lists of included studies had not been checked as per our protocol. We have now extracted data from these two omitted studies and analysed them against the themes identified in the published qualitative evidence synthesis. While the omission of Donovan et al 2003 and Stein et al 2016 has affected the richness of the accounts within the relevant themes, and potentially the number of studies contributing to individual findings and proposed changes, the omission does not substantively change the overall conclusions of the synthesis. It should be noted that given the commentary article (Audrey 2011) was included in place of the original data source (Donovan et al 2003), the original data source (Donovan et al 2003) has not been fully credited as contributing to all relevant ‘proposed changes to the main trial’ topics.

Online supplemental file 2 has been amended to add characteristics of the Protect feasibility study from Audrey et al 2011. It should also be noted that references were incorrectly numbered in online supplemental files 7; 8 and this has also been corrected. online supplemental file 9 is a new file that maps data extracted from Donovan et al 2003 and Stein et al 2016 to the themes of our qualitative synthesis.

Any future update of this synthesis should use the original source data from Donovan et al 2003 rather than the Audrey 2011 summary data and include the Stein et al 2016 study.