ANALYSIS OF THE WORKER 
investigator must carefully train his interviewers to secure, 
from a number of workers in the occupation, accounts of the 
difficulties of the job. These data are analyzed and tabu- 
lated for frequency. Such studies have been useful in re- 
vising curricula for training secretaries, librarians, teachers, 
home-makers, pharmacists, retail salespeople, specialty 
salesmen, and various types of executives. The difficulty 
analysis supplements the duty analysis. It is sometimes fol- 
lowed by a listing and evaluation of the abilities deemed 
most desirable in the worker. These abilities as listed are 
often found to be stated in terms too abstract to be very 
useful in test construction; but the process as a whole is 
often helpful and suggestive for research in vocational selec- 
tion as well as in training. 
INNATE AND ACQUIRED ABILITIES 
The distinction between innate and acquired abilities may 
be disregarded in analyzing abilities and constructing tests. 
Most of the workers with whom the investigator deals are 
adults, and even in the earlier stages of a person’s develop- 
ment his innate and his acquired abilities are practically. 
indistinguishable. It has even been maintained that the 
distinction is entirely hypothetical. Certain it is that nearly 
all abilities are modifiable—subject to adaptation and im- 
provement with practice. The question as yet unanswered 
is the extent to which some of these abilities are specifically 
determined by native endowment. F ortunately for the in- 
vestigator in vocational selection, he needs to know only 
whether a person has the abilities in question, or the capa- 
city to develop these abilities. Whether these capacities 
were defined and limited in the germ plasm or were pro- 
duced through environmental influences of infancy and 
childhood is no present concern of his. What he requires is 
a measure of the applicant’s capabilities at the time of em- 
ployment. Just what can this man do? If he has previously 
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