Choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial - the development of the DELTA2 guidance by Sones, WR, Julious, SA, Rothwell, J, Ramsay, C, Hampson, L, Emsley, R, Walters, S, Hewitt, C, Bland, M, Fergusson, D, Berlin, J, Altman, D, Vale, L, Cook, JA

DELTA2 guidance on choosing the target difference and undertaking and reporting the sample size calculation for a randomised controlled trial by Cook, J, Julious, S, Sones, W, Hampson, L, Hewitt, C, Berlin, J, Ashby, D, Emsley, R, Fergusson, D, Walters, S, Wilson, E, Maclennan, G, Stallard, N, Rothwell, J, Bland, M, Brown, L, Ramsay, C, Cook, A, Armstrong, D, Altman, D, Vale, L