Validity

Validity refers to the extent to which something does what it is intended to do. From this broad perspective, validity equally applies to an object designed to perform certain tasks, to a program targeted to certain goals, or to an instrument intended to measure a given concept or construct. Therefore, it is not limited to the problem of measurement, although it is in this context that we will use it throughout this entry. The concept of validity applies to all measurement situations, but is particularly crucial to social epidemiology, where most research work has to deal with constructs that have to be operationalized. This entry contains a brief review of the concept with emphasis on its empirical and theoretical implications.

The constructs are variables that cannot ...