EMPLOYMENT PSYCHOLOGY
other measurements of ability may be evaluated. If more
than one reliable criterion may be had, it is important that
ihe measurements be checked against each of them separately.
 Wechsler (214), for example, in his study of taxicab
 drivers, discovered that one of his tests predicted the
number of accidents the driver would have and another the
wages he would earn. The use of only one of these criteria
would have made his study half as valuable.
1. Time required to train the employee. In many occupations,
 preliminary training is given the new employee
before He is placed at work or during the early stages of
his employment while he has but little proficiency. The
cost of this supervision or special training is usually considerable,
 and other things being equal, the sooner the new
employee acquires the necessary information and skill the
greater the saving to the firm. Where the employee is required
 to reach a certain level of proficiency before being
allowed to enter active service, the criterion may be the time
required to reach the prescribed level. Some employers
guarantee to workers or salesmen a minimum rate of pay,
to which is added a bonus or a piece-rate payment when the
employee’s performance warrants it. Usually the employee
is costing the concern more than he earns until this stage
of proficiency is reached. In this case, the time required
to learn the job well enough to be earning a bonus is a useful
 criterion of initial vocational success.
2. Standing in corporation schools. If the preliminary
training takes place in a vestibule school, apprenticeship
course or other corporation school, the grades received in
this school may be used as a criterion for testing the effectiveness
 of selective methods. The instruction is ordinarily
of the practical sort which concerns itself with the particular
 operations required for the job, and the criterion often
becomes the rating of the teacher on the skill which the
student displays in these operations at the end of the course.
When possible, actual measure of this skill should be ob-34