Bayesian Estimation Improves Prediction of Outcomes after Epilepsy Surgery.

We estimated the statistical power of studies predicting seizure freedom after epilepsy surgery. We exacted data from a Cochrane meta-analysis. The median power across all studies was 14%. Studies with a median sample size or less (n<=56) and a statistically significant result exaggerated the true effect size by a factor of 5.4, while the Bayesian estimate of the odds ratio only exaggerated the true effect size by a factor of 1.6. We conclude that Bayesian estimation of odds ratios attenuates the exaggeration of significant effect sizes in underpowered studies. This result could improve patient counseling regarding epilepsy surgery.