In understanding how a variety of evidence supports or does not support alternative views of continuity, one must keep in mind certain important statistical principles. First, even if a 10-year stability coefficient is as high as .5, the best prediction one can make about any individual’s standardized aggression score 10 years later is that it will retreat 50% of the distance toward the mean for the population. Second, because aggression is always a positively skewed characteristic with many individuals scoring near zero and few scoring very high, truncating the high end of the distribution will always substantially reduce the correlation of aggression with any other variable including itself. Thus, such a reduction says little about “who” is contributing to continuity over time.
