RT Journal Article SR Electronic T1 Challenging the systems approach: why adverse event rates are not improving JF BMJ Quality & Safety JO BMJ Qual Saf FD BMJ Publishing Group Ltd SP 1051 OP 1052 DO 10.1136/bmjqs-2014-003569 VO 23 IS 12 A1 Philip Levitt YR 2014 UL http://qualitysafety.bmj.com/content/23/12/1051.abstract AB