Background:
Randomized controlled trials (RCTs) provide evidence about the effects of healthcare interventions. However, results can be undermined by flaws in design, conduct, analyses and selective reporting. Therefore, assessments of risk of bias in results of the included RCTs are mandatory in Cochrane systematic reviews. The revised Cochrane 'Risk of bias' tool (RoB 2.0) is a major update to RoB 1.0, which was introduced in 2008 and revised in 2011.

Objectives:
To explain the key concepts that underpin RoB 2.0, and gain experience in using it to assess risk of bias in RCTs.

Description:
We will present the key features of RoB 2.0:
- signalling questions that lead to algorithm-guided 'Risk of bias' judgments;
- specification of the result of interest to be assessed;
- specification of the effect of interest (that of assignment to intervention, or starting and adhering to intervention);
- derivation of an overall 'Risk of bias' judgment for the assessed result.

We will describe the domains of bias included within RoB 2.0: bias arising from the randomization process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in the measurement of the outcome, and bias in the selection of the reported result.

Since its publication in 2016, the tool has undergone minor changes, based on user feedback and the latest developments in the field. These will be described, and participants will have an opportunity to try them out on a worked example.

A worked example will be used to provide hands-on training and facilitate discussion. Participants have the option to complete their assessments in a semi-automated Excel template, and are encouraged to bring their own portable device to access detailed guidance from the internet (www.riskofbias.info). Please note that the facilitators are unable to provide printed copies of the guidance document.