THE SCOPE OF PSYCHOLOGICAL TESTS
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both the ability and the character necessary for success
and who do succeed. Therefore, in spite of the fact that
psychological tests do not suffice in the discovery of one of
the two most important factors about applicants they
nevertheless make it possible to eliminate those individuals
who do not possess the other known factor.
Thus they enable us to consummate a very great reduction
in the number of possible errors, and to bring the process
of selection much closer to the region of accuracy and
certainty.
The best and most authentic example of this process
which has been obtained is that described in Chapter III.
Here it was seen that a considerable number of inspectors
who did not pass the tests but who were hired nevertheless
were failures. This number corresponds to the first
large class of those who have not the necessary ability, and
who can be eliminated at the outset by means of the tests.
Next, there was a group who passed the tests but who
nevertheless failed. This group probably failed because
did not possess the necessary moral qualities. Finally,
there remained the group which succeeded and which
Worked for a period of from one to four months at piecework
production. This group undoubtedly possessed the
necessary moral traits and ninety-four per cent of them
bad passed the tests, showing that they had the necessary
ability. This is a very good example of the practical scope
a nd value of tests when applied to employment work,
ev en though that scope does not embrace the discovery of
every fact about an individual which the employment
office would like to know. (Moreover, the example is an
exceptionally valuable one because both those who did not
pass the tests and those who did were hired. Therefore, it
became possible to show the enormous amount of work
