It is at once evident that the preliminary trial is by no means always a measure of the final relative capacities of the individuals tested. The average of all seven coefficients increases from .41 at the preliminary trial to .92 at the one hundred and thirtieth trial. As the trials proceed then, the relative positions of the thirteen individuals become more and more definitely fixed, but in the beginning the indication is obscure. The rate of this process, however, varies with the test, and to a considerable degree. Adding shows changes in position which effect a correlation of .87 only after the twenty-fifth trial. Beyond this point there is little change, the eightieth and one hundred and thirtieth trials correlating equally well, and practically perfectly, with the final order. After twenty-five trials, then, the final capacities of the individuals in the adding test may be said to be indicated fairly accurately. Opposites, in the fiftieth trial, yields a coefficient equal to that of addition in the twenty-fifth trial, and by the eightieth trial the correlation may be said to be complete. Only after fifty trials, then, can the test be said to yield comparative measures which reflect the individual's final capacity in this form of controlled association. In the case of tapping it is only at the one hundred and thirtieth trial that the correlation with final position exceeds .69.
These results may be easily comprehended by thinking of each test (as for instance the tapping test) as a prolonged race, consisting of a large number of heats (205 separate trials). All individuals begin with a running start, their respective initial speeds depending on the momentum they have acquired through a certain amount of previous practice, and on such momentary ability and zeal as they possess at the time. But as the succeeding "heats" or trials occur some individuals who were originally in the lead begin to lose ground in relation to others who, though initially slower, are now speeding up and overtaking the leaders. Still others may retain their original relative positions to the end of the race. In the table of coefficients, a correlation of 1.00 indicates that at that point the ultimate relative positions of the contestants have at last become established. The nearer the figure approaches zero the more uncertain are the relative positions at the particular trial. To terminate the race at a point where the correlation is low and to reward the contestants according to the position they had reached at that point would be manifestly unfair to those who were still speeding up and partial to those who were losing ground.