TY - JOUR T1 - The Zen of quality improvement: the waves and the tide form a unity JF - BMJ Quality & Safety JO - BMJ Qual Saf SP - 297 LP - 298 DO - 10.1136/bmjqs-2015-004842 VL - 25 IS - 5 AU - Charles L Bosk Y1 - 2016/05/01 UR - http://qualitysafety.bmj.com/content/25/5/297.abstract N2 - Multiple problems arise when the logic of the randomised controlled trial (RCT) is used to dismiss the success of an intervention when measurable improvement occurs in the intervention groups but an equivalent improvement also occurs in the control groups.When groups both inside and outside a programme improve over the same period to the same degree according to an assigned metric, there is a secular trend that may exhibit the features of what Chen et al1 label a ‘rising tide’.But when organisations in the control groups improve just as much as those that are the subject of targeted interventions, how do we know any intervention was necessary?The rising tide phenomenon presents a confusion, a contradiction and a conundrum for logic model of the RCT, since it is constructed to eliminate bias by blinding both the researcher and subjects as to who has been randomised to the treatment arm and who the control arm, and assumes as well that the control group's data will not be contaminated by the intervention.Quality improvement programmes, as Chen et al point out, are very different. They are rarely introduced into a vacuum; rather, they are introduced into fields … ER -