The goal of some research studies is to demonstrate the existence of an effect. Statistical testing, withp less than .05, is one criterion for establishing the existence of this effect. In this situation, the fixedsample stopping rule, in which the number of subjects is determined in advance, is impractical and inefficient. This article presents a sequential stopping rule that is practical and about 30% more efficient: Once a minimum number of subjects is tested, stop withp less than .01 or greater than .36; otherwise, keep testing. This procedure keeps alpha at .05 and can be adjusted to fit researchers’ needs and inclinations.
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I thank Ira Bernstein, Peter Dixon, Arthur Samuel, and anonymous reviewers for their suggestions.
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Frick, R.W. A better stopping rule for conventional statistical tests. Behavior Research Methods, Instruments, & Computers 30, 690–697 (1998). https://doi.org/10.3758/BF03209488
- Null Hypothesis
- Monte Carlo Simulation
- Sequential Probability Ratio Test
- High Criterion
- Multiple Statistical Test