This 2-year study investigated how teaching assistants affected Dutch secondary school teachers, examining: the impact of teaching assistants on teachers' tasks, teachers' attitudes toward task relief, job satisfaction, and teacher absence. Teaching assistants were hired by 16 Dutch high schools to take over non-teaching, administrative tasks. Study participants were teachers in schools with teaching assistants and in control schools (which hired substitute teachers to reduce teacher tasks). Participants completed questionnaires on job satisfaction and task responsibility before and after the intervention, and researchers collected data on teacher absence. Some participants also completed focus groups and interviews. Results indicated that some teachers took advantage of the services of teaching assistants, and they subsequently reported task relief. However, most of the teachers found that the limited duration of the study did not allow them enough time to benefit from teaching assistants. They believed that they would have made substantial use of the assistants if the assistants had occupied permanent positions in the school. Despite the limitations, intervention group teachers were more able to focus on core teaching than were control group teachers, and they had fewer absences than did control group teachers. (Contains 40 references.) (SM)