Clinical outcome research in complementary and alternative medicine: an overview of experimental design and analysis.

This article serves as a primer for those beginning clinical research in complementary and alternative medicine. The authors provide a basic overview of important experimental design and statistical issues, of which clinical researchers in the area of complementary and alternative medicine must be aware when attempting to demonstrate the effectiveness of particular treatment modalities. As the article suggests, science is an inferential process, and experimental investigations can vary greatly in methodological integrity. Key concepts in clinical outcome research such as internal validity, statistical conclusion validity, and the appropriate measurement and operational definitions of outcomes are discussed. New scientific approaches that are evolving because of paradigm shifts in science (e.g., chaos theory) are also reviewed. Suggestions are provided to further develop an understanding of clinical outcome research methodology.