Theoretical Scope <span>How general is the theory? That is, how widely applicable is it? In most cases, a theory that may only be applied within a fairly narrow set of circumstances is not considered as useful as a theory that encompasses a very wide range of communicative interactions. The ideal, of course, is a theory that succinctly explains the nature of human communication as a whole.
</span>Appropriateness <span>Theories are often evaluated based upon how well their epistemological, ontological, and axiological assumptions relate to the issue or question being explained. If a theory recapitulates its assumptions (if it is tautological), it is not an effective theory.
</span><span>Heuristic value <span>Some theories suggest the ways in which further research may be conducted. By presenting an explanatory model, the theory generates questions or hypotheses that can beoperationalized relatively easily. In practical terms, the success of a theory may rest on how readily other researchers may continue to do fruitful work in reaction or support. </span></span> <span>Validity <span>It may seem obvious that for a theory to be good, it must also be valid. Validity refers to the degree to which the theory accurately represents the true state of the world. Are the arguments internally consistent and are its predictions and claims derived logically from its assumptions? Many also require that theories be falsifiable; that is, theories that present predictions that--if they prove to be incorrect--invalidate the theory. The absence of such questions significantly reduces the value of the theory, since a theory that cannot be proven false (perhaps) cannot be shown to be accurate, either.</span> <span>Parsimony <span>The law of parsimony (Occam's razor) dictates that a theory should provide the simplest possible (viable) explanation for a phenomenon. Others suggest that good theory exhibits an aesthetic quality, that a good theory is beautiful or natural. That it leads to an "Aha!" moment in which an explanation feels as if it fits.</span> Openness <span>Theories, perhaps paradoxically, should not exist to the absolute exclusion of other theories. Theory should not be dogma: it should encourage and provide both for skepticism and should--to whatever degree possible--be compatible with other accepted theory.</span></span></span>
