ABSTRACT
Experts and their supposedly predictive models have mesmerized local land planners and even the courts for decades. There as been a dramatic increase in the use of numerical simulation models in the earth sciences as a means to evaluate large-scale or complex physical processes. Government regulations and agencies may be required by law to establish the trustworthiness of models used to determine policy or to attest to public safety; scientists may wish to test the veracity of models used in their investigations. Numerical models may contain closed mathematical components that may be verifiable, just as an algorithm within a computer program may be verifiable. The term validation is used even more misleadingly to suggest that the model is an accurate representation of physical reality. Both the content and the format of the scientific information supplied to local planners can be intimidating, especially for lay planners with minimal experience in the environmental sciences.
