Study limitations and dissemination bias are two of the eight GRADE domains, and two of the five domains that can lead to rating down of the certainty of the evidence. Evaluating study limitations involves considering whether flaws in the design or conduct of studies in a meta-analysis could bias the effect estimate. Evaluating dissemination bias involves considering whether there are results missing from a meta-analysis that could bias the effect estimate because of the nature of the missing results.
Session 4 of the GRADE Learning Live series covers how to rate study limitations and dissemination bias in systematic reviews of interventions.
Topics include:
- What are study limitations? What is dissemination bias?
- How do these domains relate to assessments of risk of bias in Cochrane reviews? ROB2 and ROB-ME assessments.
- How to evaluate study limitations and dissemination bias in reviews of interventions
- Impact of study limitations and dissemination bias on the certainty of evidence
- Overlap with other GRADE domains
This webinar is suitable for those wanting to use GRADE to interpret and summarise findings in a systematic review. An understanding of systematic review methods and content covered in the introductory session is assumed.
Presenter Bios
Nicole Skoetz heads the Cochrane Evidence Synthesis Unit (ESU) Germany/UK and the WHO Collaborating Centre on Evidence Syntheses and Evaluation of Novel Cancer Drugs. As a medical doctor and senior editor for Cochrane, she is an active member of the Cochrane Prognosis Methods Group and the GRADE Guidance Group, contributing to methodological development in prognosis, diagnosis, and interventions. Her expertise spans non-communicable diseases, public health, and advanced synthesis methods, including rapid, living, and scoping reviews, network meta-analysis, and GRADE certainty assessment. She has coordinated major evidence syntheses and national guidelines—such as the German living guideline on COVID-19 therapy—and supported WHO and health authorities worldwide, including successful Essential Medicines List applications (e.g., PD-1 inhibitors). Under her leadership, the ESU delivers high-quality, policy-relevant evidence syntheses for complex, large-scale projects.
Jun Xia is an evidence-based healthcare researcher whose unique perspective – forged through her upbringing in China and education in the UK – informs her work in raising care standards in resource-limited settings. As Director of the Nottingham Ningbo GRADE Centre and a founding member of the China Clinical Practice Guideline Alliance (GUIDANCE), she bridges global methodological advances with local practices in China to enhance patient care through high-quality clinical guidelines. Jun has been a contributing editor and reviewer for the Cochrane Collaboration since 2005, advancing evidence-based guideline development and implementation across cultures and continents.
