Behavioral health terminology is an area beset by imprecision that results from confusing claim determinations, unnecessary evaluations, and poor outcomes that result from inappropriate treatment. In medical evaluation reports, one notes references to depression, anxiety, and stress, which are not diagnoses but often are treated as such. Behavioral factors can affect claims in four ways: the presence of a formal clinical diagnosis that meets specific criteria, psychological symptoms, difficult life circumstances, and behavioral overlays. Only the first of these can be attributed to a workplace injury or illness, and determining a causal relationship requires, at minimum, a precise diagnosis. For example, by depression does the health provider mean major depressive disorder with specifiers, persistent depressive/dysthymic disorder, adjustment disorder with depressed mood, or some other specific condition? The behavioral layers can affect the outcome of the claims process and may or may not be appropriate targets of an evidence-informed intervention aimed at returning an injured or ill worker to a higher level of function. The point is not to argue whether or not behavioral interventions are appropriate in workers’ compensation, personal injury, and other claims; the point, rather, is that precise language is the first, necessary step in sorting out the myriad ways in which behavior affects claim incidence, duration, and cost.