Lack of fitness due to drugs and alcohol has been implicated in recent calamities (oil spills, subway crashes). Bioassays (of body fluids, hair clippings, etc.) can establish whether or not certain chemicals were ingested at some point in time prior to the accident, but beg the question of whether performance itself was degraded. A performance-based assessment method would permit more direct evidence of fitness potential in the workplace and, once instituted, could be expected to improve productivity. Since tests are not actual jobs, a method is need for indexing change which provides a context or standard tied to the jobs themselves. Phase I demonstrated the feasibility of using alcohol dosage as an indexing standard and multivariate dose- equivalency equations were created to permit the "dialing in" of a set alcohol equivalency level, so that combinations of performance loss which met that level could be "flagged." Also, sensitivity in a field setting was shown using a commercial airline pilot on several transoceanic flights involving multiple time-zone changes, and an algorithm was developed to "tune" (minimize) false positive errors. Plans for Phase II are to establish further job relevancy and improved sensitivity (i.e., hit ratio) of the tests as well as minimizing false positives.