Placebo comparator group selection and use in surgical trials: the ASPIRE project including expert workshop oleh David J Beard, Marion K Campbell, Jane M Blazeby, Andrew J Carr, Charles Weijer, Brian H Cuthbertson, Rachelle Buchbinder, Thomas Pinkney, Felicity L Bishop, Jonathan Pugh, Sian Cousins, Ian Harris, L Stefan Lohmander, Natalie Blencowe, Katie Gillies, Pascal Probst, Carol Brennan, Andrew Cook, Dair Farrar-Hockley, Julian Savulescu, Richard Huxtable, Amar Rangan, Irene Tracey, Peter Brocklehurst, Manuela L Ferreira, Jon Nicholl, Barnaby C Reeves, Freddie Hamdy, Samuel CS Rowley, Naomi Lee, Jonathan A Cook