RT Journal Article SR Electronic T1 Clarifying the interrupted time series study design: the author’s reply JF BMJ Quality & Safety JO BMJ Qual Saf FD BMJ Publishing Group Ltd SP 475 OP 476 DO 10.1136/bmjqs-2015-004163 VO 24 IS 7 A1 Peter McCulloch YR 2015 UL http://qualitysafety.bmj.com/content/24/7/475.2.abstract AB