I recently discovered that GiveWell decided to exclude an outlier in their water chlorination meta-analysis. I’m not qualified to judge their reasoning, but maybe others with sufficient expertise will weigh in?
We excluded one RCT that meets our other criteria because we think the results are implausibly high such that we don’t believe they represent the true effect of chlorination interventions (more in footnote).[4] It’s unorthodox to exclude studies for this reason when conducting a meta-analysis, but we chose to do so because we think it gives us an overall estimate that is more likely to represent the true effect size.
I recently discovered that GiveWell decided to exclude an outlier in their water chlorination meta-analysis. I’m not qualified to judge their reasoning, but maybe others with sufficient expertise will weigh in?