Recently, a giant paper on carbohydrate consumption and mortality was published in The Lancet. The paper discussed the findings of a prospective cohort study and a meta-analysis of several cohort studies. Studies like this are often the ones that generate the most hype, which is always bizarre to me given
Meta-analyses are widely used to summarize and examine treatment effects. However, few researchers examine the relationship between power and meta-analyses. In this post, I discuss power conceptually and mathematically. Then I explain how different models impact power and the problems with under-powered meta-analyses.