Individual differences in intra-individual variability

For each of 75 Ss several estimates of intra-individual variations were calculated for each of 4 motor skills. The reliability of intra-individual variation for these data, estimated from Pearson productmoment correlations, ranged from r = .31 to r = .51 (in all cases p < .05). It was also found that in 3 of the 4 skills, intra-individual variation correlated significantly (r = .36, .54, .55) with mean performance level. Second order partial correlations, holding constant the effect of mean performance level, were then used to estimate the reliability of intravariation. These correlations were statistically significant and ranged from r = .27 to r = .34. When correlations of intra-individual variation were calculated among the four skills it was demonstrated that intra-individual variation was approximately 95 to 100% task specific.