Correction: The Perioperative Quality Improvement Programme (PQIP patient study): protocol for a UK multicentre, prospective cohort study to measure quality of care and outcomes after major surgery.

S Ramani Moonesinghe, Dermot McGuckin, Peter Martin, James Bedford, Duncan Wagstaff, David Gilhooly, Cristel Santos, Jonathan Wilson, Jenny Dorey, Irene Leeman, Helena Smith, Cecilia Vindrola-Padros, Kylie Edwards, Georgina Singleton, Michael Swart