It is maintained by Dr. Galton, Professor Pearson and others that ability and performance are distributed in accordance with the curve of error. It does not seem to me that this is the case. If ability for scholastic work were distributed in this way at birth, it would not remain so among college students, who are a selected group. Those unfit are less likely to be found in college and those particularly competent are more likely to be there. This would tend to give us for college students a skew curve in the negative direction. In spite of this factor, I believe that the main skew is in the opposite direction,
and that ability is distributed somewhat like wages which are roughly proportional to it. If the average earnings of men in this country are $600 a year, it is clear that the positive deviations from the average are many times the negative deviations. There may be a certain minimal ability necessary for survival, and variations and sports may occur to an extent in the positive direction not possible in the negative direction. There are certain 'constant errors,' such as a college education, which divide men into different 'species.' In so far as students are graded on the lines of the probability curve, this may measure the attitude of the examiner rather than the distribution of the men in merit.
