What is a random effects model?
A random-effects model is a statistical technique that assumes a distribution of populations, rather than a single population. It is used to provide a more realistic interpretation of the true distribution of effects across more than one population. In meta-analyses, a random-effects model is employed when the heterogeneity is so large that meta-analysis is inappropriate. It leads to a widening of the confidence interval around the overall estimate, thus providing more accuracy in the analysis. 