Quantitative assessment instruments have been developed to identify those skills or behaviors which individuals with developmental disabilities need in order to become competitively employed, and to measure individuals' progress in the program and hence measure program effectiveness. Such assessment instruments are problematic, as each employment situation uniquely requires its own particular combination of skills. An attempt to apply quantitative assessment tools in a supported employment situation found that: (1) no job situation existed which required clients to demonstrate many of the skills or behaviors listed on the assessments; (2) some skills/behaviors listed on the assessments were irrelevant to the job situation; and (3) other relevant skills/behaviors were not listed. The second purpose of assessments, the measurement of program effectiveness, is only appropriate for groups of subjects and does not appropriately measure program effectiveness for individuals. Nor is the use of single subject designs appropriate, as they call for treatments that are introduced either systematically or randomly. A qualitative process model is suggested, where the actual process of implementing the model reveals the relevant variables of the job situation. Items in a qualitative assessment are not quantified but serve as reminders of important factors to be considered. (JDD)