Fidelity and validity: issues of human behavioral representation requirements development

Within the modeling and simulation community issues of fidelity and validity are often considered the fundamental metrics used to gauge the quality and utility of a model or simulation. The extent to which a model represents reality is often referred to as fidelity while the usefulness of that representation within the context of a specific application relates to its validity. In most cases, increases in representational fidelity are coincident with increased development costs. How then does one decide where investments in fidelity should be placed? Faced with this question regarding the representation of operator behavior for a synthetic integrated air defense system (IADS) to be used in a synthetic battlespace, we are conducting a requirements analysis to establish human behavioral representation (HBR) requirements. This analysis will provide a degree of traceability from fidelity requirements to simulation objectives so effective tradeoffs can be made. The present paper reviews our methodology and preliminary findings to date.