Randomised trials, especially when brought together in systematic reviews, are regarded as the gold standard for evaluating the effects of healthcare treatments with thousands of trials and hundreds of systematic reviews reported every year. PubMed has indexed over 370,000 reports of randomised trials; the World Health Organisation’s International Clinical Trials Registry Platform contains over 250,000 trial records, of which 71,000 are listed as recruiting; and the Cochrane Central Register of Controlled Trials contains more than 800,000 records. Tens of billions of dollars of public and private money are invested globally in trials every year (US$25 billion in the US alone in 20103) and the average cost of recruiting a patient to a trial in the UK is estimated to be almost £8,500.
Much of these resources is wasted, often because results are not published, or are poorly reported. However, resources are also wasted because the research asks the wrong questions or is badly designed. Moreover, despite trials being a cornerstone of evidence-based healthcare, the methodology and infrastructure for conducting these complex studies is a largely evidence-free zone.
The Trial Forge initiative aims to make trials more efficient by looking for small gains across all trial processes, from research question through to reporting. It will encourage everyone connected with trials to be more sceptical of what we do by asking for the evidence behind all of our trial decisions. Where no evidence exists (as will often be the case), Trial Forge will provide a platform to highlight this gap and bring researchers and others (including funders) together so that they can fill the gap. Insights from disciplines not normally associated with trials, such as business and organisational change management, will be part of this efficiency drive.
Trial Forge won the 2019 Cochrane-REWARD Prize for reducing research waste (https://www.cochrane.org/news/2019-cochrane-reward-prize-winners-announced).
Trial Forge is led by Shaun Treweek at the University of Aberdeen. Further details on Trial Forge are available at http://www.trialforge.org.
Contacts
- Shaun Treweek; streweek@mac.com
Status
OngoingPublications
2026
Prowse S, Brazzelli M, Bruhn H, Treweek S. Do Funders, Regulators, and Ethics Bodies Support Informative Trials? A Content Analysis of Global Guidance Documents. J. Evaluation in Clinical Practice 2026, 32: 1. https://doi.org/10.1111/jep.70356
Alexander-Sefre A, Sherratt F, Green H, Treweek S, Shepherd V. Health experiences and inequalities across intersecting social identities in health research: a scoping review. Journal of Clinical Epidemiology 2026, doi: https://doi.org/10.1016/j.jclinepi.2025.112112
Sherratt, FC, Biggs, K, Green, HR, Bishop L, Martins de Barros C, Treweek S. Making trials more inclusive of people experiencing socioeconomic disadvantage: developing the INCLUDE socioeconomic disadvantage framework. Trials 2026. https://doi.org/10.1186/s13063-026-09448-2
2025
Dawson S, Ostrovska B, Treweek S, Gillies K, Mitham M, Devane D, Khunto K, Bower P, Parker A, Soulsby I, Green H. Sometimes different, often the same: guidance on how recruitment and retention in trials need to be tailored to enhance participation of ethnic minority groups: a qualitative interview study in England. JCE 2025, 118, 112005. https://doi.org/10.1016/j.jclinepi.2025.112005
Shepherd V., Svobodova M., Ivins, N. Russell AM, Volkmer A, Jayes M, Woolfall K, Clout M, Munnery K, Treweek S. Addressing the knowledge gap: development of stakeholder-informed training to improve the inclusion of adults with impaired capacity to consent in trials. Trials 2025, 26: 429. https://doi.org/10.1186/s13063-025-09182-1
S. Prowse, S. Treweek, M. J. P. Larrea, M. Brazzelli, and A. Uribe, “ Tackling Health Inequalities in Cancer Screening: Experiences of Eastern European and African Communities in Northeast Scotland,” Cancer Medicine 2025, 14; 18: e71236, https://doi.org/10.1002/cam4.71236.
Bruhn H, Treweek S, Weijer C, Briel M, Clarke M, Crowley R, Gillies K, Green H, Murphy E, Parker E, Shiely Hayes G, Hart P, Shiely F. Trial Forge Guidance 5: ethical considerations in randomised Studies Within A Trial (SWATs). Trials 2025, 26: 267. https://doi.org/10.1186/s13063-025-08958-9
Prowse S, Treweek S, Brazzelli M, Bruhn H. Improving trial informativeness: A rapid review of global research on how to ensure trials are useful. Journal of Evaluation in Clinical Practice, 2025; 31:e70147. https://doi.org/10.1111/jep.70147.
Alexander-Sefre A, Sherrat F, Green H, Treweek S, Shepherd V. To What Extent Does Intersectionality Affect Health Inequalities and Outcomes: A Scoping Review. Available at SSRN [8/5/2025]: https://ssrn.com/abstract=5238548 or http://dx.doi.org/10.2139/ssrn.5238548.
Daly, A., Treweek, S., Hayes, G.S., Shiely F.. Tolerating bad health research (part 2): still as many bad trials, but more good ones too. Trials 2025, 26: 110. https://doi.org/10.1186/s13063-025-08747-4
Cunningham, S., Russell, A. M., Lidington, E. & Shiely, F. Lack of data collection in clinical trials prevents us from evaluating inclusion of people with disabilities. J. Clin. Epidemiology 111715 (2025). https://www.jclinepi.com/article/S0895-4356(25)00048-4/fulltext
McGrath, ER., Kirby N., Shiely F. Use of participant data and biological samples is insufficiently described in participant information leaflets. Journal of Clinical Epidemiology, Volume 177, 111590. https://www.jclinepi.com/article/S0895-4356(24)00346-9/abstract
2024
Treweek, S., Gillies, K., Witham, M.D. DEvane, D., Khunti, K., Bower, P., Parker, A., Soulsby, I., Ostrovoska, B., Prowse, S., Green, H. How should trial teams make decisions about the proportions and diversity of the ethnic groups in their trial?. Trials 2024, 5: 768. https://doi.org/10.1186/s13063-024-08625-5
Biggs K, Hullock K, Dix C, Lane JA, Green H, Treweek S, Shiely F, Shepherd V, Willis A, Isaacs T, Cooper C. Time to STEP UP: methods and findings from the development of guidance to help researchers design inclusive clinical trials. BMC Med Res Methodol 2024; 24: 227. https://doi.org/10.1186/s12874-024-02342-y
Shiely, F., Murphy, E., Gilles, K., Hood K., O’Sullivan L., Harman N., Isaacs T., Treweek S. Trial participants’ self-reported understanding of randomisation phrases in participation information leaflets can be high, but acceptability of some descriptions is low, especially those linked to gambling and luck. Trials 2024, 25: 391. https://doi.org/10.1186/s13063-024-08217-3
Arundel, C.E., Clark, L.K., Parker, A. Beard D, Coleman E, Cooper C, Devane D, Eldridge S, Galvin S, Gillies K, Hewitt CE, Sutton C, Torgerson DJ, Treweek S on behalf of the PROMETHEUS Group. Trial Forge Guidance 4: a guideline for reporting the results of randomised Studies Within A Trial (SWATs). Trials 2024, 25: 83. https://doi.org/10.1186/s13063-024-08004-0
Parker, A., Way, R., Okanlawon, A. A., Mongelli, G., Coleman, E., Arundel, C., … Treweek, S. (2024, February 8). WP1: Identifying and prioritising trial recruitment and retention strategies. https://doi.org/10.17605/OSF.IO/CZ829
Parker A, Arundel C, Clark L, Coleman E, Doherty L, Hewitt CE, Beard D, Bower P, Cooper C, Clifford L, Devane D, Emily R, Eldridge S, Galvin S, Gillies K, Montgomery A, Sutton CJ, Treweek S, Torgerson DJ. Undertaking Studies Within A Trial to evaluate recruitment and retention strategies for randomised controlled trials: lessons learnt from the PROMETHEUS research programme. Health Technol Assess 2024, 28:2. https://doi.org/10.3310/HTQW3107
Shepherd V, Joyce K., Lewis A, Flynn S, Clout M, Nocivelli B, Segrott J, Treweek S. Improving the inclusion of an under-served group in trials: development and implementation of the INCLUDE Impaired Capacity to Consent Framework. Trials 2024, 25: 83. https://doi.org/10.1186/s13063-024-07944-x
2023
Buckley, C., Treweek, S., Laidlaw, L. Shiely F. Patient and Public Involvement (PPI) in outcome selection in breast cancer and nephrology trials. Trials 2023, 24: 93. https://doi.org/10.1186/s13063-022-06980-9
2022
Dawson S, Banister K, Biggs K, Cotton S, Devane D, Gardner H, Gillies K, Gopalakrishnan G, Isaacs T, Khunti K, Nichol A, Parker A, AM Russell, Shepherd V, Shiely F, Shorter G, Starling B, Williams H, Willis A, Witham MD and Treweek S. Trial Forge Guidance 3: randomised trials and how to recruit and retain individuals from ethnic minority groups—practical guidance to support better practice. Trials 2022, 23: 672. https://doi.org/10.1186/s13063-022-06553-w
Gardner H, Elfeky A, Pickles D, Dawson A, Gillies K, Warwick V, Treweek S. A good use of time? Providing evidence for how effort is invested in primary and secondary outcome data collection in trials. Trials (accepted). Pre-print at https://www.researchsquare.com/article/rs-1769190/v1
Clark, L. et al. (2022) ‘The PROMoting the USE of SWATs (PROMETHEUS) programme: Lessons learnt and future developments for SWATs’, Research Methods in Medicine & Health Sciences. https://journals.sagepub.com/doi/full/10.1177/26320843221089632
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. https://bmjopen.bmj.com/content/12/4/e055521
Murphy, E., Shiely, F. & Treweek, S. How much is the lack of retention evidence costing trial teams in Ireland and the UK?. Trials 23, 396 (2022). https://doi.org/10.1186/s13063-022-06223-x
Pirosca, S., Shiely, F., Clarke, M. Treweek S. Tolerating bad health research: the continuing scandal. Trials 23, 458 (2022). https://doi.org/10.1186/s13063-022-06415-5
Treweek, S., Miyakoda, V., Burke, D. Shiely F. Getting it wrong most of the time? Comparing trialists’ choice of primary outcome with what patients and health professionals want. Trials 23, 537 (2022). https://doi.org/10.1186/s13063-022-06348-z
2021
Coleman, E., Arundel, C., Clark, L., Doherty, L., Gillies, K., Hewitt, C. A., Innes, K., Parker, A., Torgerson, D., & Treweek, S. (2021). Bah humbug! Association between sending Christmas cards to trial participants and trial retention: randomised study within a trial conducted simultaneously across eight host trials. BMJ, 375, [e067742]. https://doi.org/10.1136/bmj-2021-067742
Treweek, S., Banister, K., Bower, P. et al. Developing the INCLUDE Ethnicity Framework—a tool to help trialists design trials that better reflect the communities they serve. Trials 22, 337 (2021). https://doi.org/10.1186/s13063-021-05276-8
2020
Crowley, E., Treweek, S., Banister, K. et al. Using systematic data categorisation to quantify the types of data collected in clinical trials: the DataCat project. Trials 21, 535 (2020). https://doi.org/10.1186/s13063-020-04388-x
El feky, A., Gillies, K., Gardner, H. et al. Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review. Syst Rev 9, 224 (2020). https://doi.org/10.1186/s13643-020-01471-x
Gardner HR, Albarquoni L, El Feky A et al. A systematic review of non-randomised evaluations of strategies to improve participant recruitment to randomised controlled trials [version 1; peer review: 2 approved, 2 approved with reservations, 1 not approved]. F1000Research 2020, 9:86 (https://doi.org/10.12688/f1000research.22182.1)
Pirosca S, Clarke M and Treweek S. Learning from Cochrane systematic reviews: what improvements do these suggest for the design of trials? [version 2; peer review: 2 approved]. F1000Research 2020, 9:178 (https://doi.org/10.12688/f1000research.22635.2)
Treweek, S., Bevan, S., Bower, P. et al. Trial Forge Guidance 2: how to decide if a further Study Within A Trial (SWAT) is needed. Trials 21, 33 (2020). https://doi.org/10.1186/s13063-019-3980-5
2019
Bruhn, H., Treweek, S., Duncan, A. et al. Estimating Site Performance (ESP): can trial managers predict recruitment success at trial sites? An exploratory study. Trials 20, 192 (2019). https://doi.org/10.1186/s13063-019-3287-6
Brunsdon, D., Biesty, L., Brocklehurst, P. et al. What are the most important unanswered research questions in trial retention? A James Lind Alliance Priority Setting Partnership: the PRioRiTy II (Prioritising Retention in Randomised Trials) study. Trials 20, 593 (2019). https://doi.org/10.1186/s13063-019-3687-7
Gardner HR, Treweek S, Gillies K (2019) Using evidence when planning for trial recruitment: An international perspective from time-poor trialists. PLoS ONE 14(12): e0226081. https://doi.org/10.1371/journal.pone.0226081
2018
Treweek, S., Bevan, S., Bower, P. et al. Trial Forge Guidance 1: what is a Study Within A Trial (SWAT)?. Trials 19, 139 (2018). https://doi.org/10.1186/s13063-018-2535-5
El Feky A, Gillies K, Gardner H, Fraser C, Treweek S. A protocol for a systematic review of non- randomised evaluations of strategies to increase participant retention to randomised controlled trials. Systematic Reviews; 2018 Feb 16;:1–7. https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-020-01471-x
Healy, P., Galvin, S., Williamson, P.R. et al. Identifying trial recruitment uncertainties using a James Lind Alliance Priority Setting Partnership – the PRioRiTy (Prioritising Recruitment in Randomised Trials) study. Trials 19, 147 (2018). https://doi.org/10.1186/s13063-018-2544-4
2016
Gardner, H.R., Fraser, C., MacLennan, G. et al. A protocol for a systematic review of non-randomised evaluations of strategies to improve participant recruitment to randomised controlled trials. Syst Rev 5, 131 (2016). https://doi.org/10.1186/s13643-016-0308-3
2015
Treweek, S., Altman, D.G., Bower, P. et al. Making randomised trials more efficient: report of the first meeting to discuss the Trial Forge platform. Trials 16, 261 (2015). https://doi.org/10.1186/s13063-015-0776-0