A note on the inconsistency inherent in the necessity to perform multiple comparisons.

The comparison of multiple groups raises the question of the appropriate unit in which to evaluate the research. Thus it would be possible to hold errors constant per comparison, per hypothesis, per experiment, per group, or even per S. "… the most defensible decision is to divide our work into separate tests of hypotheses and to hold constant the expected number of errors per hypothesis tested." (PsycINFO Database Record (c) 2010 APA, all rights reserved)