CRITERIA OF VOCATIONAL SUCCESS 5
tained at the conclusion of the training period and used in
place of the instructors’ estimates.
3. Quantity and quality of output. In spite of the precautions
 their use requires, measures of quantity and
quality of output are on the whole the most useful criteria.
These measures may be in terms of the quantity and quality
of work turned out per unit of time, or of the amount sold
(when salesmen are being compared), provided, of course,
the workmen are doing or making or selling the same thing,
have had comparable experience, and are not limited or
restricted in their output by management or working conditions.
 These measures of production should be expressed
as the average amount produced over an extended period of
time.
In developing improved tests for the selection of postoffice
 clerks and railway mail clerks, the Director of Research
 of the United States Civil Service Commission, Dr.
L. J. O'Rourke (124), gave much attention to the selection
of criteria—measures of actual ability of the men on the
job. He arranged with the Chicago post-office to weigh the
first-class mail distributed daily by a representative group
of 124 clerks during a six-month period. The average number
 of pounds distributed by each clerk, together with the
time in minutes required to do it, constituted his first criterion
 of ability. A second criterion was the record in a
monthly examination or test to determine how accurately
and quickly each clerk can distribute into his own distribution
 case. To these objective measures of ability were
added a third criterion—foremen’s ratings. The combined
criteria gave a satisfactory measure of actual ability as a
mail sorter, and made possible the validation of the new
type of civil service test by means of which 60,000 to 80,000
applicants a year are now examined, more easily, accurately,
and fairly than before, with much less expense to the government
 and with measurable improvement in the average
ability of applicants selected.
When salesmen are being compared according to the

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