Measurement Error

Measurement is the assignment of symbols, usually numbers, to objects according to a rule. Measurement involves both creating a rule and making assignments. The symbols to be assigned represent attributes of the object. Error in measurement is any deviation of the assigned symbol from the "true" value that should be designated to the object. A term that is used to refer to how accurately something is measured is construct validity.

For example, a researcher might want to measure a person's level of education. In this case, the person is the "object" and level of education is the "attribute" for which the researcher wants a value assigned to each object. The goal of measurement is to assign to the person a symbol—a number—that represents her or his ...