How a meta-analysis turns ten conflicting trials into one answer
1 September 2026 · Cohira team
Ten small trials, half positive, half null. Reading them one by one gets you an opinion. Pooling them gets you an estimate.
What pooling does
A meta-analysis weights every eligible study by its precision and combines them into a single pooled effect with a confidence interval, a measure of how much the studies disagree, and an honest read on how much to trust the result.
Reading the forest plot
Each line is a study: the square is its estimate, the whiskers its uncertainty. The diamond at the bottom is the pooled answer. If the diamond clears the line of no effect, the evidence points somewhere.
When the question is bigger than A versus B
When several treatments have never been tested against each other, a network meta-analysis joins every trial into one connected network, estimates the missing comparisons, and ranks the options with the certainty stated.
Done right, the whole exercise is pre-registered, PRISMA-reported, and reproducible, which is exactly what reviewers check first.