Introducing the risk of bias tool for non-randomized studies

Tags: Workshop
Sterne J1, Reeves B2, Shea B2, Savovic J3, Higgins JPT3, Turner L4
1University of Bristol, 2Non-Randomised Studies Methods Group, 3University of Bristol, UK, 4Ottawa Hospital Research Institute, Canada


To introduce ACROBAT-NRS, the new risk of bias tool for non-randomized studies (NRS), to those who may use Cochrane intervention reviews, and to obtain feedback.


It is sometimes appropriate to include NRS in reviews, but the existing risk of bias tool is applicable only to trials. This workshop will give an overview of the new ACROBAT-NRS tool, an extension to the existing risk of bias tool for application to NRS. The tool structure groups a series of signalling questions under bias domains, influenced by both the existing risk of bias tool for RCTs and the QUADAS-2 tool for diagnostic test accuracy studies. The workshop will be split into two parts:

1. Introduction: providing a brief overview of the development and structure of the new tool, including worked examples (30 min), followed by a time (15 minutes) of quiet for participants to familiarize themselves with the tool.

2. Discussion and feedback: a structured, facilitated discussion focusing on:

- clinical and epidemiological expertise to assess risk of bias in NRS, and how authors and Review Groups might obtain or verify this;

- implications for reviews if the tool is widely adopted in Cochrane;

- implications for the next version of the risk of bias tool for randomized trials;

- developments required for guidance and software;

- phase-in timelines.

Check the programme for two other workshops on aspects of ACROBAT-NRS.