Fig. 1

Power when performance is operationalized as GSV versus V-scale. A The results for each impairment level in the younger age range conditions. B The results for each impairment level in the older age range conditions. Impairment level refers to SD below average, such that 5 corresponds to the most impaired condition. Power is the proportion of 5000 simulations where the t test of the group difference controlling for baseline score had a p value < .05. The dotted reference line is at 90%