Precursors can be thought of as existing physical or contextual factors as well as the causes of the health condition. Required antecedent factors are those elements that must be present for the health problem to come into existence or are direct precursors of it. For example, required factors may include genetic predisposition, being in the right place at the right time, prior exposure and vulnerability, or legal or policy conditions. From an asset perspective, required factors might also include variables such as the political clout of the local representatives or the existence of economic empowerment zones. The predisposing factors of health services utilization models generally fall into the required antecedent factors category.
Causal factors are those elements that influence whether the health problem will manifest itself, given the presence of the required antecedents. Depending on the health problem, causal factors
the development of a logic model but also to tailoring the programmatic intervention and to designing the evaluation of the program’s effect.