] EMPLOYMENT PSYCHOLOGY 
guidance and placement, in gaging abilities with reference to 
a number of occupations. For vocational selection, however, 
a total score has much more predictive value, is easier to 
obtain, and is less subject to individual errors. If the inves- 
tigator merely wishes to know the number of tests in which 
the person obtains a high score, he will find that this is 
expressed better numerically. The profile method has the 
advantage of graphic presentation, but a graphic method of 
presenting a total score may also be easily devised. 
Another way of predicting from a battery of tests is to 
give the most valid and reliable test first. If the applicant’s 
score in ‘this test clearly predicts success, the applicant is 
hired. If it clearly predicts failure, the applicant is re- 
jected. If it leaves the matter in doubt, the series of tests is 
continued until success or failure is unequivocally predicted. 
But if the applicant is accepted, the series should be com- 
pleted in order that there may be no serious gaps in test rec- 
ords when the check-up of predictions is made later on. This 
method has little to recommend it over a total score. 
The same statistical methods of evaluation and prediction 
may be applied to the total score as to scores in any single 
test. The total score should, of course, have more predictive 
value than the score in any one test. 
This completes our outline of statistical procedures useful 
in determining the reliability and the validity of the tests 
and in securing from them their maximum predictive value. 
We shall now consider what economic savings these predic- 
tions imply, 
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