Test Validity
Test validity measures the accuracy of a test in assessing what it is intended to measure. In psychological and educational testing, validity refers to the extent that evidence supports the interpretations of test scores and their intended use. While classical models classified validity into content validity, criterion validity, and construct validity, the dominant view today considers it a single construct.
Validity and Reliability
Validity is distinct from reliability, which measures the consistency of a test. While adequate reliability is essential for validity, it does not guarantee the validity of a measure. For instance, a highly reliable test may measure something unrelated to its intended purpose.
Validation Process
To establish test validity, a comprehensive validation process involves gathering evidence to support the proposed interpretations of test scores. This process begins by defining the intended use of the test and identifying potential threats to its validity. Researchers then collect evidence in five categories to support or question the validity of the interpretations.
Evidence for Validity
Evidence to support validity can fall into several categories:
- Content-based: Examines the alignment of the test content with the intended construct.
- Response-based: Assesses how individuals respond to test items.
- Internal structure: Analyzes the relationships within the test items themselves.
- Relations to other variables: Explores the correlations between test scores and other relevant measures.
- Consequences: Considers the impact of testing on individuals or groups.
The integration of this evidence leads to a validity argument that may necessitate revisions to the test, its administration, or the underlying theoretical constructs. If any changes are made, a new validation process is required to support the updated version.