The study was conducted in three phases: (a) pre-test; (b) intervention; and (c) post-test
Pre-test. Using the 'Structured Observation of Students' Participation in Class', each student in both groups was observed four times during different lessons (with a 1-week interval between observations) to establish a baseline for level of participation. All pre-test observations were conducted between the 2nd and 3rd months of the school year, by an occupational therapist with 8 years of experience working with children with developmental delays. The observer was trained in using the 'Structured Observation of Students' Participation in Class' and was not blinded to the schools' assignment (Co-PID or IS). During this period the teachers, who were blinded to the school assignment, were asked to teach in a regular manner without changing the content or design of their lessons. Next, the teachers filled out the School Function Assessment questionnaire for each student. Finally, based on the 'Structured Observation of Students' Participation in Class' scores and teachers' familiarity with the students' function, the occupational therapist and each of the participating teachers jointly filled-out the 'Goal Attainment Scaling' form. Each student had three goals, one for each of the participation skills: Communicating, Choosing and Initiating. Post-test. This phase was conducted during the 9th and 10th months of the school year, and was identical to the pre-testing phase in terms of both process and measures used