At present, there exists no widely agreed upon set of study-design selection criteria for systematic reviews of health systems research, except for those proposed by the Cochrane Collaboration's Effective Practice and Organisation of Care (EPOC) review group (which comprises randomized controlled trials, controlled clinical trials, controlled before-after studies, and interrupted time series).
17 The types of studies we considered eligible were randomised controlled trials, controlled clinical trials, controlled before and after studies, and interrupted time series analyses (meeting the quality criteria of the Cochrane Effective Practice And Organisation of Care Review Group).
Of these, only randomised controlled trials, controlled clinical trials, controlled prospective studies and, controlled before and after studies were considered for inclusion so that evidence from interventions provided plausibility or probability of effectiveness [ 15].
We considered study designs in the following order: overviews of systematic reviews and systematic reviews, randomised controlled trials, cluster-randomised controlled trials, quasi-randomised controlled trials, controlled before-and-after studies, and interrupted time-series analyses.
Systematic reviews, randomised controlled trials, quasi randomised controlled trials, controlled before-after studies and interrupted time series were eligible study designs.
We included the most recently published high quality systematic reviews and any randomised controlled trials, non-randomised controlled trials, controlled before after studies or interrupted time series studies published subsequent to the systematic review.
We excluded narrative reviews and systematic reviews that did not include acceptable study designs (i.e., randomized controlled trials, quasi-randomized controlled trials, controlled before-and-after studies, interrupted time series or before-and-after studies); and evaluate at least one of the specified organizational interventions; or measure treatment completion.
Study designs eligible for this review were systematic reviews, randomized controlled trials (RCT), quasi-randomized controlled trials, controlled before-after studies and interrupted time series.
We included studies identified in any language using the search strategy with the following study design: systematic reviews, randomized controlled trials (RCT), non-randomized controlled trials, controlled before and after studies (CBAs), and interrupted time series (ITS) (defined as at least three measurements before and three after the introduction of accreditation and/or certification).
References of included studies were hand-searched, and registers of clinical trials were searched (Clinical Trials, Current Controlled Trials, controlled-trials.com, National Health Service Research and Development Health Technology Assessment Programme (HTA), National Institute of Health, ClinicalTrials.gov).gov
Studies could be randomised trials, cluster-randomised trials, controlled-clinical trials and before-and-after studies.
