Parsons, Nick RStallard, NigelParsons, HelenHaque, AminulUnderwood, MartinMason, JamesKhan, IftekharCosta, Matthew LGriffin, Damian RGriffin, JamesBeard, David JCook, Jonathan ADavies, LorettaHudson, JemmaMetcalfe, Andrew2022-11-222022-11-222022-10-01Parsons, N R, Stallard, N, Parsons, H, Haque, A, Underwood, M, Mason, J, Khan, I, Costa, M L, Griffin, D R, Griffin, J, Beard, D J, Cook, J A, Davies, L, Hudson, J & Metcalfe, A 2022, 'Group sequential designs in pragmatic trials : feasibility and assessment of utility using data from a number of recent surgical RCTs', BMC Medical Research Methodology, vol. 22, no. 1, 256. https://doi.org/10.1186/s12874-022-01734-21471-2288PubMedCentral: PMC9526271https://hdl.handle.net/2164/19586Funding The work reported here is funded by the Efficacy and Mechanism Evaluation (EME) Programme, an MRC and NIHR partnership. The funding body had no other role in the work reported here and played no part in writing the manu- script. The views expressed in this publication are those of the authors and not necessarily those of the funding body or the MRC, NIHR or the UK Department of Health and Social Care.181984413engData CollectionFeasibility StudiesHumansMedical FutilityRecordsSample SizeR MedicineSupplementary Informationhttps://doi. org/10.1186/s12874-022-01734-2RJournal article10.1186/s12874-022-01734-2221