Table 1

The five sources of validity evidence3

1. Evidence based on test content
The relationship of the item themes, wording and format with the intended construct, including administration process
2. Evidence based on response processes
The cognitive processes and interpretation 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 external variables
The pattern of relationships of test scores to external 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 under-representation or construct-irrelevant variance