Related Experiment Video
Updated: Aug 9, 2025

Author Spotlight: Evaluating the Adjuvant Efficacy and Safety of Angong Niuhuang Pill in Viral Encephalitis Treatment
Published on: April 19, 2024
Most Cochrane systematic reviews and protocols did not adhere to the Cochrane's risk of bias 2.0 tool
Ana Luiza Cabrera Martimbianco1,2, Kamilla Mayr Martins Sá3, Giovanna Marcílio Santos3
1Hospital Sírio-Libanês, Centre of Health Technology Assessment, - São Paulo (SP), Brazil.
Objective:
The aim of this study was to identify the frequency of Cochrane systematic reviews and Cochrane systematic reviews protocols using (or planning to use) the risk of bias 2.0 tool to assess the risk of bias of the included randomized clinical trials.
Study Design:
This is a meta-research study.
Methods:
We included Cochrane systematic reviews or Cochrane systematic reviews protocols that planned to include randomized clinical trials. We assessed the Cochrane Database of Systematic Reviews and screened for issues published after the launch of risk of bias 2.0 tool (2019-2022). Two independent investigators performed the study selection and data extraction.
Results:
We analyzed 440 Cochrane systematic reviews and 536 Cochrane systematic reviews protocols. Overall, 4.8% of the Cochrane systematic reviews and 28.5% of the Cochrane systematic reviews protocols used or planned to use risk of bias 2.0 tool. Although low, adherence is increasing over time. In 2019, 0% of Cochrane systematic reviews used risk of bias 2.0 tool, compared to 24.1% in 2022. In Cochrane systematic reviews protocols, adherence increased from 6.9% in 2019 to 41.5% in 2022. A total of 274 (62.1%) Cochrane systematic reviews had their protocols published before 2018; only one used risk of bias 2.0 tool and reported the change of versions in the "Differences between protocol and revision" section.
Conclusion:
The Cochrane's risk of bias 2.0 tool has low adherence among Cochrane protocols and systematic reviews. Further efforts are necessary to facilitate the implementation of this new tool.
Related Concept Videos
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...
Bias in Epidemiological Studies
Study Designs in Epidemiology
Observational studies are those where the researcher does not intervene but rather observes natural variations. They include cross-sectional, cohort, and...
Relative Risk
Bias
In statistics, a sampling bias is created when a sample is collected from a population, and some members of the population are not as likely to be chosen as others (remember, each member...
Systematic Error: Methodological and Sampling Errors
Sampling errors originate from improper sampling methods or the wrong sample population. These errors can be minimized by refining the sampling strategy. Defective instruments or faulty calibrations are the sources of instrumental...

