The reported project attempted to determine if formal inservice training improves the performance of paraprofessional aides in the classroom. Ninety-two teachers at four elementary schools examined the administrative, clerical, supervisory, instructional, and housekeeping duties most frequently performed by paraprofessionals and rated them on the effectiveness of their performance by responding to a questionnaire. The results indicate that paraprofessional aides who participate in a formal inservice training program and those who receive incidental on-the-job training basically perform the same kinds of duties, with their performance differing in frequency, variety, and competence. It was further revealed that formal inservice training programs place great emphasis on specific duties, which tends to restrict the aide to tasks within the scope of that training; while incidental on-the-job training programs promote the performance of a greater variety of tasks. The investigation suggests that, to be practical and effective, inservice programs for paraprofessional aides should be designed at the local school level and should involve both the formal and the informal aspects of training. (Author)