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 tabulated
 for frequency. Such studies have been useful in revising
 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 followed
 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 selection
 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 development
 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 improvement
 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 investigator
 in vocational selection, he needs to know only
whether a person has the abilities in question, or the capacity
 to develop these abilities. Whether these capacities
were defined and limited in the germ plasm or were produced
 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 employment.
 Just what can this man do? If he has previously

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