ABSTRACT
In many areas of psychology, and other disciplines in the behavioral sciences, it is often not possible to measure directly the concepts of primary interest. Two obvious examples are intelligence and social class. In such cases, the researcher is forced to examine the concepts indirectly by collecting information on variables that can be measured or observed directly, and which may also realistically be assumed to be indicators, in some sense, of the concepts of real interest. The psychologist who is interested in an individual’s “intelligence,” for example, may record examination scores in a variety of different subjects in the expectation that these scores are dependent in some way on what is widely regarded as intelligence but are also subject to random errors. Further, a sociologist, say, concerned with people’s “social class,” might pose questions about a person’s occupation, educational background, home ownership, etc., on the assumption that these do reflect the concept in which he or she is really interested.
