What is Power Analysis?


What is power in statistics, and how does it relate to the size of my sample?

This is a common question we hear from doctoral students doing quantitative analysis in their research. They may know who they want to survey or interview, but selecting the size of the sample is a mystery.  In this case, the tool to help you is power analysis.

Power analysis is a method to determine how large a sample is needed for statistical judgments that are accurate and reliable, and how likely the selected statistical test is to detect effects of a given size in a particular situation.  We just added a new resource to our library that steps you through the basics and points you to additional references on this very useful statistical tool.  You can find it here: