A simple, clear blog post explaining what observed power (post-hoc power) is and why it is a “useless statistical concept”.
What is this resource and what does it offer: This is a blog post by a respected educator entitled “Observed power, and what to do if your editor asks for post-hoc power analyses”. It is short and easy to follow, and uses graphs to relay key points. There are links to published articles for those who wish to explore the topic in more depth. The author also provides guidance on what to answer reviewers who request a post-hoc power calculation.
Who created this resource: Daniel Lakens, PhD Social Psychology, is an associate professor in the Department of Human-Technology Interaction, Eindhoven University of Technology, in the Netherlands. His award-winning teaching focuses on research methods for young scholars; he has created two free Coursera courses and a free online textbook on statistical methods. His blog is called “The 20% Statistician” because, in his words, “understanding 20% of statistics will improve 80% of your inferences.”