An accessibly-written webpage about the fundamentals of power and sample size.
Read: Introduction to power analysis
What the resource offers
This webpage is an excellent read for an investigator looking for a thorough description of the basics of power and how they pertain to planning a research study. Overall the language is informal and accessible to those with little statistical training. Major topics include:
- Knowing your research project
- What you need to know to do a power analysis
- Obtaining the necessary numbers to do a power analysis
- Factors that affect power
There is also a discussion about the issues of small sample sizes and sampling variation, multiplicity, and post-hoc power analyses. Examples are given using SPSS Sample Power, but they are still useful for understanding power and sample size calculations in other software.
Helpful hint: If you’re short on time, check out the “Conclusions” section at the end of the page.
Who it's for
- Clinical investigators
Who created it
This site is run by the University of California Los Angeles Institute for Digital Research and Education.