What is the main purpose of construct validity?

The main purpose of construct validity is to establish whether a test actually measures the theoretical construct it claims to measure. This involves demonstrating that the test is not only related to other measures that it should be related to (convergent validity) but also distinct from measures it should not be related to (divergent validity). In essence, construct validity is critical because it assesses the underlying theory associated with a test, ensuring that the test is relevant and appropriate for the psychological traits or behaviors it aims to evaluate.

For instance, when developing a test for depression, construct validity would ensure that the test accurately reflects the theoretical aspects of depression rather than measuring unrelated constructs, such as anxiety. Thus, a test with strong construct validity provides confidence that its results are meaningful and applicable to the construct it targets.