Models in Environmental Regulatory Decision Making (2007) / Chapter Skim
Currently Skimming:
5 Model Selection and Use
5 Model Selection and Use
Pages 170-189
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 170... ...
5 Model Selection and Use The last and perhaps most important stage of the life cycle of a regulatory model is its application to an environmental regulatory issue. How a model arrives at the point of application and how much of its development is specific for a given application vary greatly.
|
From page 171... ...
Model Selection and Use 171 BOX 5-1 Example of a Generic Model for Application to Specific Settings A description of one example of model application information is found at EPA's Support Center for Regulatory Atmospheric Modeling web site (EPA 2006l)
|
From page 172... ...
. The community of air quality modelers is highly specialized and relatively small, and the selection of models is often based on familiarity.
|
From page 173... ...
Model Selection and Use 173 BOX 5-2 Appendix W: EPA's Guidelines on Air Quality Models The guidelines, first published in April 1978, was developed to ensure consistency and standardization of model applications for air quality regulations. The guidelines was written in an effort to balance consistency and accuracy in selecting appropriate models.
|
From page 174... ...
174 Models in Environmental Regulatory Decision Making BOX 5-3 Arsenic in Drinking Water: Model Selection Morales et al.
|
From page 175... ...
Model Selection and Use 175 (a)
|
From page 176... ...
176 Models in Environmental Regulatory Decision Making BOX 5-4 Use of Multiple Models of Varying Complexity for Estimating Mercury in Fish A potential benefit of the clean-air mercury rule, which requires reductions in mercury emissions from coal-fired power plants, is the reduction of human exposure and related health impacts from methylmercury by reducing concentrations of this toxin in fish. There are many challenges and uncertainties in understanding the impact of reductions in atmospheric mercury emissions on human health.
|
From page 177... ...
This center is intended to help to promote the use and understanding of the Models-3 air quality modeling suite, including through training courses. The courses are open to everybody (including federal and state employees and scientists from the private sector and academia)
|
From page 178... ...
178 Models in Environmental Regulatory Decision Making BOX 5-6 Confidence Building in Models Through Transparency Placing data sources, software, and the exact list of commands used to produce the model output, along with a good amount of documentation, on a public web site can help build confidence in the specific use of a model. iHAPSS, the internet-based Health and Air Pollution Surveillance System, developed at the Johns Hopkins University, provides an example of this kind of resource.
|
From page 179... ...
Model Selection and Use 179 tions and application limitations. Although modelers often have no choice but to use a model for an application in which a major assumption within the model is directly violated or is close to being violated, such an application must be made clear to those who might use or review model results.
|
From page 180... ...
180 Models in Environmental Regulatory Decision Making which may conflict with regulatory time lines, and resources, which may conflict with other priorities. Such conflicts should be explicitly dealt with rather than used as a broad excuse not to collect data.
|
From page 181... ...
Model Selection and Use 181 Another example in which the use of a model involves extrapolation beyond data or assumptions occurs when EPA forecasts the results of policy decisions into the future. Under such circumstances, EPA often applies models to forecast the impact of regulations over time horizons of years to decades, sometimes incorporating demographic forecasts and forecasts of economic activities (usually from other agencies)
|
From page 182... ...
182 Models in Environmental Regulatory Decision Making and that the impacts of important assumptions can be assessed through sensitivity and uncertainty analysis. Specifying Uncertainty At the model application stage, it is important to have effective strategies for representing and communicating uncertainties.
|
From page 183... ...
Model Selection and Use 183 The focus of this effort is typically the EPA policy makers, but it can also include stakeholders who use a model to provide information to EPA, stakeholders who want independent evaluation of the utility of a regulatory model, or even members of the public who must decide whether to change behaviors or to take other actions based on model results. Most of these individuals have one thing in common -- they are not technically expert modelers.
|
From page 184... ...
184 Models in Environmental Regulatory Decision Making tion is presented can affect its interpretation. One conclusion that came from interviews with EPA decision makers was the need for more contextual information to accompany any graphic or tabular representations of model uncertainties (Krupnik et al.
|
From page 185... ...
Model Selection and Use 185 The best way for a modeler to protect his intellectual investment in a model is to claim trade-secret protection. Protection is immediate and is accomplished by insisting that the model and its contents are secret.
|
From page 186... ...
186 Models in Environmental Regulatory Decision Making BOX 5-7 Proprietary Components of Environmental Models 1. The source code: This code defines the fundamental function of the model, for example, the computational solution of the mathematical equations representing the underlying theory or code that defines the auxiliary features of the model (for example, graphic user interface)
|
From page 187... ...
Model Selection and Use 187 Department of Transportation. IBM has been hired to commercialize this model by developing user interfaces that will allow users to develop model input, run the model, and visualize the output (Ducca 2004)
|
From page 188... ...
188 Models in Environmental Regulatory Decision Making • An agency could insist on an expiration date for the secrecy protections on the model. • An agency could insist that the modeler obtain a patent rather than protect its property interest through trade-secret protections (a patent requires the public dissemination of the contents of the model)
|
From page 189... ...
Model Selection and Use 189 that is equivalent to peer review for public models. If necessary, nondisclosure agreements could be used for experts to perform a thorough review of the proprietary portions of the model.
|
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.