Direct-care service providers offering programs to individuals with developmental disabilities face a daily challenge in selecting training and work tasks that are appropriate for the abilities of the clients. An assessment tool that has considerable predictive validity for selecting such tasks is the Assessment of Basic Learning Abilities test (ABLA: Kerr, Meyerson, & Flora, 1977). Thus far, however, research and applications using the ABLA test have been conducted largely by graduate students. The purpose of this research was to investigate the efficacy of a Self-Instructional Manual (SI-M) for teaching direct-care service providers to use the ABLA test for assessing individuals with developmental disabilities, and for analyzing training tasks according to the highest ABLA levels that clients must pass in order to learn such tasks readily. The research included four progressive studies to assess an SI-M for the ABLA test. The results demonstrated that, after studying the SI-M and practising with a partner for approximately six hours, direct-care service providers met mastery criteria for knowledge of the ABLA, applying the test to assess clients, and classifying training and work tasks according to the highest level of the ABLA needed to perform them. Moreover, the SI-M was considerably more effective in accomplishing these tasks than was the original description of the ABLA test.