What is a model?
A model is a simplification of reality that is constructed to gain insights into select attributes of a particular physical, biological, economic, or social system.
A computational model uses measurable variables, numerical inputs, and mathematical relationships to produce quantitative outputs.
Which models should be included in the Models KBase?
The goal is to include all computational models, which are developed, used or supported by EPA Offices that deal with the continuum of processes that translate human activities and natural system interactions into human health and environmental impacts.
What information about the models is included in the Models KBase?
There are three parts to the Models KBase: General Information, User Information and Model Science.
The "General Information" section provides an overview of the model, contact information for the model, and a link to its home page. The overview of the model is intended to give a short description of what the model does and what it is used for as well as any substantive changes that have recently occurred and any plans for further model development.
The "User Information" section includes the technical requirements to run the model, a link to the user's guide, the necessary inputs, the basic outputs and any other information necessary for model use.
The "Model Science" section presents the conceptual basis of the model, the science behind the model, the model framework (equations and algorithms), and information about the model evaluation.
Does including a model in the Models KBase signify an endorsement or EPA "Stamp of Approval"?
No. The fact that a model is in this Models KBase does not necessarily mean that EPA endorses the model; conversely, the fact that a model is not included does not mean that it may not be appropriate for a particular use.
As noted in the CREM guidance on models, the appropriate use of a model depends on the particular purpose to which it is applied. Not knowing every purpose for which a model may be used, EPA has resisted the idea of endorsing or even ranking or "scoring" models in this KBase. Rather, the Agency hopes that model usersóby using the information in this KBase and by relying on recommendations provided by the CREM guidance on models ówill make an informed choice when using a model. EPA recommends that models should only be used for the particular application for which they were designed and only after they have been appropriately evaluated. Decisions about the suitability of a specific model for a particular application should be made in consultation with experienced model users (viz. EPA staff, EPA contractors, or staff of other agencies), as necessary.