Difference between Model and theory

Thank you SAGE (and authors Shoemaker, Tankard, Lasorsa, 2012):

Noting that model is sometimes used as a synonym for theory, Kaplan (1964b) rightly asked, “If ‘model’ is coextensive with ‘theory,’ why not just say ‘theory’?” (p. 264). The answer is that although they are sometimes confused, there is a good reason to keep the two terms conceptually distinct. A theory is a set of systematically related generalizations suggesting new observations for empirical testing. As such, the purpose of a theory is to explain or predict. A model does not explain or predict anything. We might say that the purpose of a model is to describe and imagine.

Though a model is not a theory, a model can be used to represent a theory. As Neuliep (1996) noted, “Theorists use models because they can describe and simulate physical, logical, or conceptual processes that may not otherwise be observable or presentable” (p. 30). He gave the example of theories of listening. Because listening is a psychological phenomenon impossible to touch, a model can provide a valuable method of indirect observation. Neuliep stated that models enable theorists to illustrate, delineate, and depict the structural features (i.e., what the object or process looks like—its form) and functional features (i.e., what the object or process actually does—its purpose) of their theories in varying degrees of abstractness and detail. Some models may be very detailed and literal and others rather general and abstract. No matter how detailed or literal a model is, however, it is nothing more than a description of an object or process. If we want to understand how the object or process works, we need something more—a theory.

Full text can be found here:

http://sk.sagepub.com/books/how-to-build-social-science-theories/n7.xml?term=lasswell