These videos, originally part of the RoB 2: Learning Live webinar series, explain how to use the first domain of the RoB 2: bias arising from the randomisation process. The presenters provide an overview of the empirical evidence for including this domain, and the relevance of the signalling questions. Topics covered included generation of the allocation sequence, concealment of the allocation sequence and the role of baseline imbalance in assessing risk of bias. The presenters showed the algorithm for how answers to signalling questions are mapped to judgements about risk of bias for the domains, along with worked examples. Finally, they also demonstrated a Microsoft Excel tool that has been developed for implementation of RoB 2.
This session was intended for people who are interested in using RoB 2 to assess risk of bias in their review. In addition to review author teams, CRG editors can learn about the risk of bias arising from the randomisation process so that they are able to assist authors with any queries they may have and also ensure information included in the review for this domain are relevant.
The webinar was delivered in June 2020 and below you will find the videos from the webinar, together with accompanying slides to download [PDF].
Part 1: An overview of how bias can arise during the randomization process
Part 2: Allocation concealment and evidence of problems during randomization from baseline imbalances
Part 3: Assessing risk of bias from the randomization process in RoB 2
Part 4: A worked example
Alexandra McAleenan is a Senior Research Associate in the University of Bristol’s Department of Population Health Sciences. Under the supervision of Professor Julian Higgins, she is currently performing both diagnostic and prognostic systematic reviews in brain cancer. She has a keen interest in sources of bias in randomised and non-randomised studies of interventions, particularly quasi-experimental studies. Alexandra is working on the ongoing development of ROBINS-I, prior to which she contributed to the development of RoB 2. Alexandra gained a PhD in Molecular Biology from Imperial College London in Professor Luis Aragon's research group. She holds a MBiochem from the University of Oxford. Outside of work, Alexandra enjoys learning circus skills, and has developed a new love of cross-country skiing.
Jelena Savović is Senior Research Fellow in Evidence Synthesis in the University of Bristol’s Department of Population Health Sciences and Evidence Team Lead at the NIHR Applied Research Collaboration West. Jelena is an epidemiologist with expertise in evidence synthesis. She contributed to the development of several risk of bias tools, for randomised trials (RoB 2), non-randomised studies of interventions (ROBINS-I) and for systematic reviews (ROBIS). Her empirical work exploring the sources of bias in randomised trials informed the development of the Cochrane risk of bias tool and the revised RoB 2 tool.