Criterion-Related Validity. A simple example will illustrate how criterion-related validity
can be established. Assume that a sales job requires employees to have a high level of
customer service orientation, and an organization decides to implement a selection test
that assesses prospective applicants on their customer service skills. In order to show that
the customer skills assessment is a valid predictor of performance, it must be shown that
individuals who score higher on the assessment perform better on the job and individuals
who score lower on the assessment perform less well on the job. Thus, validity in this
case would be defined as a meaningful relationship between how well people performed
on the assessment and how well they subsequently performed on the job.
To measure the extent of the relationship between performance on a test and performance
on a job, a correlation coefficient is used. A correlation coefficient is a statistical
measure that indicates the strength of the relationship between scores on an assessment
and scores on a job performance measure, such as performance appraisal ratings.
Correlations range from 0 (meaning there is no relationship between how well individuals
perform on an assessment and how well they perform on the job) to 1.00 (meaning
there is a perfect relationship between how well individuals perform on an
assessment and how well they perform on a job—the highest scorer on the assessment
receives the highest performance appraisal score, the second highest scorer on the
assessment receives the second highest performance appraisal score and so forth).
Correlation coefficients that measure the validity of assessment methods never reach
1.00, because performance on an assessment can never perfectly predict how well individuals
will perform on a job. Other factors inevitably influence job performance, such
as an individual’s motivation, relationships with co-workers and supervisors and a myriad
of other factors. Assessment methods that organizations typically use tend to have
validities (or correlation coefficients) in the .30 to .50 range. Although these are less
than the maximum possible validity of 1.00, assessments with validities in this range
nonetheless provide very useful and valuable information for making selection decisions.