Exploring power in response inhibition tasks using the bootstrap: The impact of number of participants, number of trials, effect magnitude, and study design

Publication date: Available online 10 December 2019Source: International Journal of PsychophysiologyAuthor(s): Curtis D. Von Gunten, Bruce D. BartholowAbstractA primary psychometric concern with laboratory-based inhibition tasks has been their reliability.However, a reliable measure may not be necessary or sufficient for reliably detecting effects (statistical power). The current study used a bootstrap sampling approach to systematically examine how the number of participants, the number of trials, the magnitude of an effect, and study design (between- vs. within-subject) jointly contribute to power in five commonly used inhibition tasks. The results demonstrate the shortcomings of relying solely on measurement reliability when determining the number of trials to use in an inhibition task: high internal reliability can be accompanied with low power and low reliability can be accompanied with high power. Moreover, adding additional trials once sufficient reliability has been reached can result in large gains in power. One reason for the partial dissociation between reliability and power was due to the number of participants contributing little to reliability. Another reason was that the number of trials had a much larger influence on power in within-subject designs. For between-subject designs, the probability of detecting small-to-medium-sized effects with 150 participants was generally <55%. However, effect size was positively associated with number of trials. Thus, rese...
Source: International Journal of Psychophysiology - Category: Psychiatry & Psychology Source Type: research