128 
EMPLOYMENT PSYCHOLOGY 
results computed in the manner previously described. 
Below is a table showing the correlation between the final 
rankings of each foreman and the ranking based on three 
tests taken together: 
Correlations 
ist Group (12) 90 
2nd Group (11) 65 
3rd Group (12) 50 
The correlations in groups two and three are not as high 
as those in the first. However, group two had met only 
sixteen times which, at two and one-half hours a session, 
meant only four days of actual work. The third group 
had met only twelve times, which meant only three days 
of actual work. Consequently, although the correlations 
between the opinion of the instructors and the rank of 
the pupils in the tests are already significant, their true 
significance cannot be stated until more time has elapsed. 
It may or may not be significant that the trend of the 
correlations varies directly with the length of time which 
has expired. 
In order to obtain a true estimate of the ability of a 
group of apprentices and trained workers, it is necessary 
to give to the entire group a thoroughgoing practical 
examination in the work which they are supposed to have 
learned. Very few apprentice schools make a practice of 
this precaution. They assume that when a boy has passed 
through their various grades and classes of work, he is 
qualified to serve as a full-fledged journeyman. This 
assumption is patently unjustified. Moreover, it in 
creases the difficulty of obtaining reliable information 
about the relative abilities of a class of apprentices and