THE SCOPE OF PSYCHOLOGICAL TESTS I9I 
A second impediment in the way of selecting big men 
by tests is the necessity of trying out preliminary tests 
on a large group of individuals all doing exactly the same 
kind of work. Unless tests are tried on a large scale, the 
probable errors are likely to make the results worthless; 
and unless all the individuals involved are doing the same 
kind of work, it is impossible to compare their relative 
ability as workers with their relative ability in the various 
tests. In the experiments described here, there were 
generally twenty or more subjects in each group. And 
m most cases, the members of the various groups were 
engaged in exactly the same kind of work. This condition 
is very common in factories, where quantity production 
and the fine division of labor have made it necessary for 
huge groups of individuals to engage in the same process 
°f production. However, the higher we go in the scale 
°f work, the more difficult it is to find this condition. 
Very few men in important positions are engaged in tasks 
tvhich are exactly the same, and therefore, it is almost 
impossible to compare them with each other so as to ob 
tain a record of their relative abilities. Even where the 
names of a number of positions are alike, it by no means 
follows that the tasks performed are also alike. No one 
is more familiar with this condition than the employment 
manager whose duty it is to secure men for a large number 
°f important positions alike in name but very different 
m fact. 
Finally, even if the members of a group are engaged in 
the same kind of work, it is essential that the work be of 
s uch a nature as to furnish an objective measure of pro 
duction. By an objective measure of production is 
lUeant simply an impersonal record of the amount and 
Quality of work done by each individual. We have seen