Crowley, EvelynTreweek, ShaunBanister, KatieBreeman, SuzanneConstable, LyndaCotton, SeonaidhDuncan, AnneEl Feky, AdelGardner, HeidiGoodman , KirsteenLanz, DorisMcDonald, AlisonOgburn, EmmaStarr, KathStevens, NatashaValente, MarieFernie, Gordon2020-06-172020-06-172020-06-16Crowley, E, Treweek, S, Banister, K, Breeman, S, Constable, L, Cotton, S, Duncan, A, El Feky, A, Gardner, H, Goodman , K, Lanz, D, McDonald, A, Ogburn, E, Starr, K, Stevens, N, Valente, M & Fernie, G 2020, 'Using systematic data categorisation to quantify the types of data collected in clinical trials : the DataCat project', Trials, vol. 21, no. 1, 535, pp. 535. https://doi.org/10.1186/s13063-020-04388-x1745-6215SCOPUS: 85086686457ORCID: /0000-0001-9646-3904/work/93483387ORCID: /0000-0002-2189-3755/work/98344088ORCID: /0000-0002-2796-6898/work/118192870ORCID: /0000-0002-7239-7241/work/186968375https://hdl.handle.net/2164/14515We would like to thank Joanne Palmer and all attendees of the 2015 workshop at the UK Trial Managers’ Network meeting. We thank all Chief Investigators of the trials in our sample for giving their permission to use their trial data collections forms in our analysis: Annie S Anderson (ActWELL), Doreen McClurg (AMBER), Charles Knowles (CONFIDeNT), Augusto AzuaraBlanco (EAGLE), Frank Sullivan (ECLS), Shakila Thangaratinam (EMPiRE), Kevin Cooper (HEALTH), Eugene Dempsey (HIP), Craig Ramsay (iQUAD), Ian Reid (KANECT), David Murray (KAT), Saruban Pasu (PIMS), Khalid S Khan (SALVO), Robert Pickard (SUSPEND), Anthony King (TAGS), Graham Devereux (TWICS), Adrian R Martineau (ViDiFlu), Charis Glazener (VUE). Similarly, we thank the funders of all the trials: Chief Scientist Office (CSO), Scottish Government Health Directorate; CSO, Scottish Government and Oncimmune Ltd; European Commission within the Seventh Framework Programme; National Institute for Health Research - Efficacy and Mechanism Evaluation (NIHR-EME); National Institute for Health Research - Health Technology Assessment (NIHR-HTA) programme; National Institute for Health Research - Programme Grants for Applied Research (NIHR-PGAR); the Scottish Government. The Health Services Research Unit, University of Aberdeen, receives core funding from the CSO of the Scottish Government Health Directorates.101518132engPROTOCOLIMPACTR Medicine (General)Pharmacology (medical)Medicine (miscellaneous)Supplementary DataR1Journal article10.1186/s13063-020-04388-xhttp://www.scopus.com/inward/record.url?scp=85086686457&partnerID=8YFLogxK211