My PI is having me run a post-hoc power analysis on our samples, with a treatment and control group and a binary outcome. I was using this website to start the process. However, at the end, the website cautions:
The Dangers of Post-Hoc Analysis
Post-hoc power analysis has been criticized as a means of interpreting negative study results.2 Because post-hoc analyses are typically only calculated on negative trials (p ≥ 0.05), such an analysis will produce a low post-hoc power result, which may be misinterpreted as the trial having inadequate power.
As an alternative to post-hoc power, analysis of the width and magnitude of the 95% confidence interval (95% CI) may be a more appropriate method of determining statistical power.
What does this mean? How would I use the width of the CI to determine if the statistical power was adequate? Is there a common threshold that I should consider?