Cover: Is It You or Your Model Talking?

Is It You or Your Model Talking?

A Framework for Model Validation

Published 1992

by James S. Hodges, James A. Dewar


Download eBook for Free

FormatFile SizeNotes
PDF file 1.7 MB

Use Adobe Acrobat Reader version 10 or higher for the best experience.


Purchase Print Copy

 Format Price
Add to Cart Paperback43 pages $20.00

This report lays out a conceptual framework for validation, arguing that some models can be validated and used to predict, while others cannot be validated and may only be put to nonpredictive uses. To be validatable, a model must be observable and measurable, must exhibit constancy of structure in time, must exhibit constancy across variations in conditions not specified in the model, and must permit the collection of ample data. Nonvalidatable models can be used as a bookkeeping device, as an aid in selling an idea of which the model is but an illustration, as a training aid to induce a particular behavior, as part of an automatic management system whose efficacy is not evaluated by using the model as if it were a true representation, as an aid to communication, as a vehicle for a fortiori arguments, and as an aid to thinking and hypothesizing. The report shows that the appropriate form of model quality assurance depends fundamentally on how the model is used.

This report is part of the RAND report series. The report was a product of RAND from 1948 to 1993 that represented the principal publication documenting and transmitting RAND's major research findings and final research.

This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit

RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.