Explanations > Social Research > Design > Types of validity
Construct | Content | Internal | Conclusion | External | Criterion | Face | Threats | See also
In a research project there are several types of validity that may be sought. In summary:
* Construct: Constructs accurately represent reality.
* Convergent: Simultaneous measures of same construct correlate.
* Discriminant: Doesn't measure what it shouldn't.
* Internal: Causal relationships can be determined.
* Conclusion: Any relationship can be found.
* External: Conclusions can be generalized.
* Criterion: Correlation with standards.
* Predictive: Predicts future values of criterion.
* Concurrent: Correlates with other tests.
* Face: Looks like it'll work.
Construct validity
Construct validity occurs when the theoretical constructs of cause and effect accurately represent the real-world situations they are intended to model. This is related to how well the experiment is operationalized. A good experiment turns the theory (constructs) into actual things you can measure. Sometimes just finding out more about the construct (which itself must be valid) can be helpful.
Construct validity is thus an assessment of the quality of an instrument or experimental design. It says 'Does it measure the construct it is supposed to measure'. If you do not have construct validity, you will likely draw incorrect conclusions from the experiment (garbage in, garbage out).
Convergent validity
Convergent validity occurs where measures of constructs that are expected to correlate do so. This is similar to concurrent validity (which looks for correlation with other tests).
Discriminant validity
Discriminant validity occurs where constructs that are expected not to relate do not, such that it is possible to discriminate between these constructs.
Convergence and discrimination are often demonstrated by correlation of the measures used...