FIGURE 2.1 The main components of problem formulation

FIGURE 2.1 The main components of problem formulation (adapted from USEPA 1998). 

Integration of available information is an iterative process that normally occurs throughout problem formulation (USEPA 1998). In general, for probabilistic assessments there will be a greater emphasis on obtaining information in quantitative rather than qualitative forms. In particnlar, probabilistic assessments require increased attention to obtaining information on 

For example, existing databases and risk assessment publications often omit statistical measnres of variability or nncertainty and sample sizes and rarely report the underlying data. These types of information are rarely used in deterministic assessments but are a fundamental reqnirement for probabilistic assessments. 

Assessment endpoints are measurable ecosystem characteristics that represent management goals (USEPA 1998). They should define 

The assessment endpoint should be not only measurable (at least potentially) but also modelable. Defining a modelable endpoint is likely to require close discussion between an assessor (who knows what they can model) and a risk manager (who knows what they want to protect). Sometimes the assessment endpoint is only indirectly related to the management goal, for example, if the assessment endpoint is a risk to individuals, but the aim is to protect population sustainability. In such cases, qualitative inference will be required to interpret the assessment result. This inference will need to be done jointly by the risk assessor and risk manager. It is likely to involve substantial uncertainty, which will have to be taken into account qualitatively when producing a narrative description of the assessment outcome. This step should be identified as part of the conceptual model. 

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