ABSTRACT
When designing a new study, researchers frequently must answer the critical question, “How many participants do I need?” The adage “the more participants the better” does not provide a concrete suggestion for researchers to use as a guidepost. Numerous rules of thumb have been generated and used as simple heuristics by researchers when determining necessary sample sizes. Often, these rules of thumb specify minimum sample sizes for particular analyses (e.g., N > 100 for multiple regression) or they specify a ratio of the number of participants needed relative to other aspects of the analyses (e.g., ratio of # of participants to # of variables).
