Assessing bias in selection of participants into the study in a Cochrane systematic review which includes non-randomised studies of an intervention (NRSI)

2.45 - 4.15pm

Objective

The workshop aims to train review authors to assess the risk of bias in selection of participants into the study, using an extended risk of bias tool (ACROBAT-NRSI), when including NRSI in a systematic review about the effects of an intervention.

Description

Cochrane recommends that review authors consider and justify whether or not to include NRSI for all research questions about the effects of interventions.  Decisions to include NRSI may arise when there are inadequate or no RCTs but where the question addressed by the review is a considered a priority.  Topics about possible harmful or long term effects of interventions, or review questions about the effects of public health and non-pharmacological interventions, may have these characteristics.  This workshop aims to give review authors and others intending to include NRSI in Cochrane systematic reviews experience in applying ACROBAT-NRSI (an extended risk of bias tool for this situation).  Unlike RCTs, NRSI do not necessarily consider an inception cohort, with a well-defined time of entry. Participants will mainly work in small groups to answer ‘signalling questions’ about selection of participants related to both intervention and outcome, and the timing of the intervention and start of follow-up, to identify the risk of bias in this domain; then, they will judge whether a the finding from a study for a particular review outcome is at high or low risk of material bias in the domain.  Responses to signalling questions and domain specific bias judgements are made on four-point scales and include a ‘no information’ option; these features will be contrasted with the existing risk of bias tool.

Target audience

Review authors intending to include non-randomised studies of an intervention (NRSI) in a Cochrane systematic review of the effects of an intervention and editors involved with such reviews.

Presenters

Barney Reeves; Jelena Savovic

Contributors

Beverley Shea, Julian Higgins, Jonathan Sterne, George Wells

Barney Reeves

Jelena Savovic