Fidelity, Resolution, Accuracy, and Uncertainty

Abstract

The basic idea of modeling and simulation (M&S) fidelity is “correspondence with reality.” There are a variety of concepts regarding what is involved in M&S fidelity and about how fidelity should be measured and described. Since the level of fidelity required is one of the main M&S cost drivers, it requires careful atten-tion. Higher fidelity increases the cost of M&S development and usually increases the cost of using the M&S. Fidelity is an important factor in M&S assessments, such as verification, validation, and accreditation. Due to the increasing reliance upon M&S results in all areas of modern science and engineering, the capability to establish confidence in M&S correctness and in the appropriateness of results for particular applications has increasing importance. Establishing such confidence in M&S results depends critically upon proper determination of fidelity. Some con-fuse fidelity with validity. Fidelity is an absolute indication of M&S results corre-spondence with reality, while validity is a relative indication of appropriateness of M&S results for a specified purpose. Validity normally uses fidelity information about the M&S as part of the basis for assessment of M&S appropriateness for a specified purpose. This chapter presents a basic concept of M&S fidelity; one which is generally compatible with many contemporary approaches. Then it discusses dimensions and attributes of M&S fidelity. Finally the chapter addresses a number of issues often encountered with M&S fidelity.