When people are asked to evaluate their own abilities, the assessments they provide tend to be self-serving. Indeed, often the appraisals that people endorse appear to be favorable to a logically impossible degree.

Perhaps the most direct demonstration of self-serving appraisal is the above average effect. When asked to judge their own capacities and performances in a specific domain against those of their peers, people predominantly respond, “I'm above average.” The above average effect has been demonstrated in the realm of driving ability (Svenson, 1981), ethics (Baumhart, 1968), health (Larwood, 1978: Weinstein, 1980), and managerial skills (Larwood & Whittaker, 1977). The most extreme documentation of this phenomenon comes from a survey conducted by the College Board in 1976–1977 of 1 million high school students. When rating themselves vis-á-vis their peers, 70% rated themselves as above average in leadership ability, whereas only 2% judged themselves as below average. When considering athletic ability, 60% considered themselves above the median and only 6%, below. When asked to judge their ability to get along with others, all students rated themselves as at least average, 60% placed themselves in the top 10%, and 25% placed themselves in the top 1%. The extremity of the phenomenon in this particular survey might be chalked up to youthful exuberance, although the above average effect occurs even among older and more educated people.