Slides from a short presentation at the World Conference of Science Journalists in 2019, with links to backgrounder posts.
Systematic Reviews &
World Conference of Science Journalists
2 July 2019
Studies are a collection of parts of
uneven quality & quantity [+ spin]
Pitfall 1: Exaggerating the quantity of
• 82 studies, published 31 meta-analyses
• 84% of those analyses combined 20 or fewer
studies – 58% had 10 or fewer
• The most studies in any one meta-analysis
Common error: exaggerating the amount
21 studies with approx 42,000 women
. . .
Sherrington et al (2019). Exercise for preventing falls in older people living in the community.
8 studies with fewer than 2,700 people
From the Summary of Findings table:
Pitfall 2: Overestimating the strength of
From 2008 Cochrane review:
Update in 2012:
5 tips for understanding data in meta-analysis: bit.ly/5TipsData
5 key things to know about meta-analysis: bit.ly/MetaBasics
Another 5 things to know about meta-analysis: bit.ly/MetaTraps
Systematic reviews & meta-analyses 5 step checkup: bit.ly/MetaCheckup