Objectives:
1. Discuss intervention complexity and challenges of systematic reviews of complex interventions
2. Discuss possible methods to overcome issues associated with systematic reviews of complex interventions
3. Discuss methodological and statistical challenges of including non randomized trials in a systematic review

Description: The main purpose of this workshop is to have an open discussion about the problem of intervention complexity. Some preliminary work on methods to identify and better describe complex interventions will be presented for discussion. The Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria for non randomised study inclusion (specifically interrupted time series and controlled before-after designs) will be presented. Description of analytical methods for systematic reviews containing studies of multiple designs will be discussed.

Target audience: Those involved in doing or supporting reviews of complex interventions and/or non randomised studies.

Style: Discussion workshop