In recent years the academic community has increasingly been calling on researchers to focus on the substantive, rather than statistical, significance. In this project I explore effect sizes in corporate governance research, and investigate whether corporate governance scholars are focusing on the substantive significance of their findings when interpreting their results. I analyze all published corporate governance research published in FT45 journals from 2009 to 2014 and find that the average effect size in corporate governance research is small, and that the majority of published studies are not able to detect the desired effects reliably as they lack statistical power. More concerning, I find that a large amount of authors ignore the substantive significance of their findings, and instead focus on statistical significance. The result of these practices has led to invalid inferences and high Type II error rates in corporate governance research.