Formulated problem verification as an explicit requirement of model credibility

Abstract

This paper deals with the formulation and formulation verifica tion of a class of problems to which "modeling solutions" are applied. Two main objectives are to develop a procedure for problem formulation and to propose indicators for the for mulated problem verification. The class of problems considered is analyzed in two categories as requiring prescriptive or descrip tive solutions. A detailed study of each category results in a pro cedure to guide the analyst during the problem formulation. This procedure is illustrated by a traffic intersection problem. The for mulated problem is measured by using indicators to accomplish an evalution for the formulated problem verification. Indicators are developed to measure (1) the probability of failing to solve the actual problem, (2) the acceptability of an alternative set of possible outcomes, and (3) how well the formulated problem is structured. An evaluation questionnaire, included in the Ap pendix, is employed in applying the proposed indicators.