Conceptual Model
Risk cannot be managed unless it has been properly assessed, and some form of model provides the best assessment process (Haimes 2004). The EPA framework relies on a conceptual model, and it has two principal components: (a) a risk hypothesis describing predicted relationships among stressor, exposure, and assessment endpoint response, along with rationales for their selection; and (b) diagrams illustrating these relationships.
By highlighting what we know and do not know about a system, a conceptual model provides an opportunity for others to evaluate explicit expressions of the assumptions underlying decisions. Conceptual models can represent many relationships, including exposure scenarios qualitatively linking land-use activities to stressors (EPA 1998). A conceptual model for the fire/fish risk problem compares short-term effects of fuel treatment project implementation to long-term effects with and without fuel treatment, including project benefits from reducing post-wildfire environmental damage. Sediment production is the environmental effect analyzed. The idea that active management can improve conditions is a testable risk hypothesis that can be visualized and communicated in a conceptual model diagram.
- Cause-and-effect Hypothesis : In the problem formulation phase of the EPA framework the objective of the analytical phase of the assessment is called the endpoint.
- Conceptual Model Diagram : The objective of fuel treatment is modification of fire behavior.
Encyclopedia ID: p3157
