Do-it-yourself meta-analysis

Dynomight has looked at the health effects of vitamin D supplementation. The large-scale meta-analyses that have been performed conclude there is no significant effect, even though individual studies relatively consistently point in the direction of an effect. This means our failure to detect a significant effect may be due to low experiment power.Dynomight suggests a mechanism for that: what if the low power of the existing randomised trials is because they tend to be run in countries that fort...