A clinical psychologist has designed a new 15-item self-report questionnaire to measure state anxiety in university students. To evaluate this new questionnaire, they administer it to a sample of 40 students alongside a widely-accepted, pre-existing anxiety scale. A correlation coefficient of +0.88 is found between the two sets of scores.
What has been demonstrated by this procedure?
Test-retest reliability
Concurrent validity
Inter-observer reliability
Face validity
