The Role of Modeling
"Fundamentally, the reason for modeling is a lack of full access, either in time or space, to the phenomena of interest. In areas where public policy and public safety are at stake, the burden is on the modeler to demonstrate the degree of correspondence between the model and the material world it seeks to represent and to delineate the limits of that correspondence."
The use of models has increased significantly. Although, models do not generate "truth", they can provide analyses and information used to inform the EPA's decision making process. Policy decisions should be informed by the best information and data. However, researchers are confronted with many constraints when obtaining data [e.g. time, access, and resources (funding, equipment, staff)].
Where there is a shortage of data and information, models can be used to provide useful insight. In general, models can help users study the behavior of ecological systems, design field studies, interpret data, and generalize results (EPA, 2009a). Models are used to make long- and short-term forecasts to extrapolate from the past and answer "what-if" questions. Models can also be used to provide concise summaries of data, in both diagnostic and regulatory contexts (NRC, 2007).
The relationship between data and models is changing. The increasing availability of data may promote new model development or application of existing models to new data. However, this requires that data are used appropriately with models. The limitations from uncertainties and assumptions associated with any model must be considered - as with observational data - before model generated results are applied in any context.