In this type of validity, it is attempted to test psychologically real constructs that have an independent existence in the test taker, and that the test scores represent the degree of presence or absence of this very real property. In this response, Cronbach and Meehl (1955) state:
This type of validity takes place when an investigator believes that his instrument reflects a particular construct, to which are attached certain meanings. The proposed interpretation generates specific testable hypotheses, which are a means of confirming or disconfirming the claim (p. 284).
This is perhaps the most complex of the validity types discussed so far. This type of validity is an essential topic in second language acquisition research precisely because many of the variables investigated are not easily or directly defined. In research, construct validation refers to the degree to which the research adequately captures the construct of interest. Construct validation can be enhanced when multiple estimates of a construct are used.