What type of validity measures the complete range of the domain being tested?

Content validity refers to the extent to which a test measures the entire range of the concept or construct it aims to assess. Essentially, it ensures that all aspects of a given domain are represented in the test items and that they reflect the specific skills, knowledge, or behaviors that should be measured.

For example, if a test is designed to measure mathematical ability, content validity would require that the test includes questions covering all relevant areas of mathematics, such as addition, subtraction, multiplication, and division, rather than just a few selected topics. When a test demonstrates strong content validity, it is more likely to accurately assess what it intends to measure, increasing the reliability of the results.

In contrast, criterion validity focuses on how well one measure predicts an outcome based on another measure. Construct validity assesses whether a test truly measures the theoretical construct it claims to measure, by exploring relationships with other variables. Face validity, while it may seem related, simply refers to how appropriate the test appears to be at face value, which does not necessarily guarantee that the complete domain is covered.