Error and Bias in Comparative Judgment: On Being Both Better and Worse than We Think We are

People believe that they are better than others on easy tasks and worse than others on difficult tasks. Previous attempts to explain these better-than-average and worse-than-average effects have invoked bias and motivation as causes. This paper develops a more parsimonious account, the differential information explanation, which assumes only that people typically have better information about themselves than they do about others. When one's own performance is exceptional (either good or bad), it is often reasonable to assume others' will be less so. Consequently, people estimate the performance of others as less extreme (more regressive) than their own. The result is that people believe they are above average on easy tasks and below average on difficult tasks. These effects are exacerbated when people have accurate information about their performances, increasing the natural discrepancy between knowledge of self and others. The effects are attenuated when people obtain accurate information about the performances of others.