Validity of assessment

Validity of assessment:

Validity focuses on whether a test actually succeeds in testing the competencies that it is designed to test. No valid assessment methods that measure all facets of clinical competence have been designed. If an instrument is not reliable over time, it cannot be valid, as results can vary depending upon when it is administered. An instrument can be both valid and reliable, either, or neither. However, it must be reliable to be valid.

Although three primary approaches to test validity are reported by Mason and Bramble (1989), Patton (2002) details the associated sub-categorical types of measurement validity:
• Content validity: Warrants that an overall sample of the content being measured is represented. Identification of the content must be accurately represented by the test items. A panel or grouping of content experts is typically consulted to identify a broad spectrum of content.
• Criterion Validity: Targets the accuracy of a measure itself. Examining criterion validity is demonstrated by comparing the selected measure with another valid measure.
• Predictive validity: Predicts a recognized association between the identified construct and something else. Typically, one measure occurs at an earlier time and is used to predict a later measure.
• Concurrent validity: Exists when the identified measure positively correlates with a measure that has been previously found to be valid. The two measures could be for the same or different constructs that are related.
• Construct validity: Ensures that the assessment measures the construct it claims to measure. Construct validity can be determined by demonstration of comparative test performance results (differential-groups study) or pre and post-testing of implementation of the construct (intervention study). This type of validity can also show how the measure relates to other measures as a defined in the construct.