QUESTION TRADE TESTS 
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be developed by means of the technique of psychology 
if they are to be at once practical and reliable. 
A further development of the question method is to 
base the questions asked on pictures or blueprints. A tool 
maker, for instance, might be shown a group of blueprints 
calling for operations on different machine tools and asked 
to name, offhand, various machines which are required 
for each. A machinist might be shown a picture of a 
collection of machine parts and tools and asked to name 
them. A third method is to give the applicant an op 
portunity to demonstrate his ability by giving him some 
representative task to perform. This type of test will 
be more fully discussed in a following chapter. 
In formulating and standardizing tests for trades and 
other technical occupations, too much emphasis cannot 
be placed upon the close cooperation between the tech 
nical expert and the psychologist. The former alone can 
supply the facts necessary for the meat of a test. However, 
it is equally true that the technical expert cannot, as 
a rule, use his knowledge in the manner required by an 
employment test or interview. This deficiency must be 
supplemented by the psychologist, whose assistance in 
formulating the details and standards of a test and in 
giving it an experimental trial, is indispensable to its 
success. 
Even when the tests to be used have already been de 
vised by experts elsewhere, their installation in another 
company should be handled with equal caution. Tech 
nical experts from that company should be called on to 
examine the proposed tests and to see whether they really 
apply to their work. After the necessary revisions have 
been made, the tests should be tried out according to 
the usual method to see if they actually correlate. It is