Face validity and criterion validity are two important concepts in the field of measurement and assessment. They both relate to the quality of a measurement instrument, but they focus on different aspects.
Face Validity
Face validity refers to the appearance of a measurement instrument. It is about whether the instrument looks like it measures what it is supposed to measure. In other words, does it seem plausible and reasonable to the test-takers and observers?
Example: A questionnaire designed to measure anxiety should include questions that are clearly related to anxiety symptoms, such as worry, nervousness, or fear. If the questionnaire includes questions about physical health or personal relationships, it would have low face validity.
Criterion Validity
Criterion validity, on the other hand, focuses on the relationship between the measurement instrument and an external criterion. This criterion can be another measurement instrument, a behavioral observation, or a real-world outcome.
Types of Criterion Validity:
- Concurrent validity: This type of validity compares the scores on the new measurement instrument to the scores on an already established and validated instrument that measures the same construct.
- Predictive validity: This type of validity assesses how well the new instrument can predict future behavior or outcomes.
Example: A new test designed to predict job success should have high predictive validity. This means that the test scores should be correlated with actual job performance.
Key Differences
| Feature | Face Validity | Criterion Validity |
|---|---|---|
| Focus | Appearance | Relationship to external criterion |
| Evaluation | Subjective | Objective |
| Evidence | Judgment based on experts and test-takers | Statistical analysis |
| Importance | Important for initial assessment | More crucial for establishing the instrument's usefulness |
In summary, face validity is a superficial assessment of an instrument, while criterion validity provides a more rigorous evaluation of its accuracy and predictive power.
