- Construct validity
In science (e.g. social sciences and psychometrics), construct validity refers to whether a scale measures or correlates with the theorized psychological scientific construct (e.g., "fluid intelligence") that it purports to measure. In other words, it is the extent to which what was to be measured was actually measured. It is related to the theoretical ideas behind the trait under consideration, i.e. the concepts that organize how aspects of personality, intelligence, etc. are viewed. The scale seeks to operationalize the concept, typically measuring several observable phenomena that supposedly reflect the underlying psychological concept. Construct validity is a means of assessing how well this has been accomplished. In lay terms, construct validity answers the question: "Are we actually measuring (are these means a valid form for measuring) what (the construct) we think we are measuring?"
A construct is not restricted to one set of observable indicators or attributes. It is common to a number of sets of indicators. Thus, "construct validity" can be evaluated by statistical methods that show whether or not a common factor can be shown to exist underlying several measurements using different observable indicators. This view of a construct rejects the operationist past that a construct is neither more nor less than the operations used to measure it.
Evaluation of construct validity requires that the correlations of the measure be examined in regards to variables that are known to be related to the construct (purportedly measured by the instrument being evaluated or for which there are theoretical grounds for expecting it to be related). This is consistent with the multitrait-multimethod matrix of examining construct validity described in Campbell and Fiske's landmark paper (1959). Correlations that fit the expected pattern contribute evidence of construct validity. Construct validity is a judgment based on the accumulation of correlations from numerous studies using the instrument being evaluated.
There are variants of construct validity:
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