HRM textbook

178 PART 2 RECRUITMENT, PLACEMENT, AND TALENT MANAGEMENT
FIGURE 6-1 Correlation
Examples
Test Score Time 2
Test Score Time 2
Test Score Time 1 Test Score Time 1
Figure 6-1 illustrates correlation. In both the left and the right scatter plots, the
psychologist compared each applicant s time 1 test score (on the x-axis) with his or
her subsequent test score (on the y-axis). On the left, the scatter plot points (each
point showing one applicant s test score and subsequent test performance) are
dispersed. There seems to be no correlation between test scores obtained at time 1
and at time 2. On the right, the psychologist tried a new test. Here the resulting
points fall in a predictable pattern. This suggests that the applicants test scores
correlate closely with their previous scores.
Validity
Reliability, while indispensable, only tells you that the test is measuring something
consistently. It does not prove that you are measuring what you intend to measure.
A mismanufactured 33-inch yardstick will consistently tell you that 33-inch boards
are 33 inches long. Unfortunately, if what you re looking for is a board that is
1 yard long, then your 33-inch yardstick, though reliable, is misleading you by
3 inches.
What you need is a valid yardstick. Validity tells you whether the test (or yardstick)
is measuring what you think it s supposed to be measuring. 12
A test, as we said, is a sample of a person s behavior, but some tests are more
clearly representative of the behavior being sampled than others. A typing test, for
example, clearly corresponds to an on-the-job behavior. At the other extreme,
there may be no apparent relationship between the items on the test and
the behavior. This is the case with projective personality tests. Thus, in the
Rorschach Test sample in Figure 6-2, the psychologist asks the person to explain
how he or she interprets an ambiguous picture. The psychologist uses that interpretation
to draw conclusions about the person s personality and behavior. In such
FIGURE 6-2 A Slide from the
Rorschach Test
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