Table 1 The five sources of validity evidence [7, 49]

1.

Evidence based on test content

The relationship of the item themes, wording and format with the intended construct, and administration including scoring.

2.

Evidence based on response processes

The cognitive processes and interpretations of items by respondents and users, as measured against the intended construct.

3.

Evidence based on internal structure

The extent to which item interrelationships conform to the intended construct.

4.

Evidence based on relations to other variables

The patterns of relationships of test scores to other variables as predicted by the intended construct.

5.

Evidence based on validity and the consequences of testing

Intended and unintended consequences, as can be traced to a source of invalidity such as construct underrepresentation or construct-irrelevant variance.