Analytical method comparison based upon statistical power calculations

Testing for the equivalence of results generated by different analytical methodology is a common practice in the pharmaceutical sciences. Methodology changes are implemented for both scientific and economic reasons during a scientific study. Thus, the need to demonstrate the appropriateness of considering data generated by distinct methods as part of a single information population arises. This paper describes a rapid and simple approach to the statistical design and interpretation of method comparison experiments. The approach presented is based upon a statistical power calculation technique, a knowledge of the variability associated with the methods to be compared and the criteria for equivalence (the limits within which differences become immeasurable or, for practical purposes, insignificant). Reference tables are included which show necessary sample sizes for comparison experiments for common combinations of these three variables.