RT Journal Article SR Electronic T1 Correction JF BMJ Quality & Safety JO BMJ Qual Saf FD BMJ Publishing Group Ltd SP 396 OP 396 DO 10.1136/qshc.2008.028068corr1 VO 20 IS 5 YR 2011 UL http://qualitysafety.bmj.com/content/20/5/396.2.abstract AB