This fourth annual study reports on state practices in 1999-2000 concerning reporting on the participation and performance of students with disabilities in statewide assessments. Unlike previous reports, the unit of analysis was the state assessments rather than all publicly available print reports. The report describes the assessment systems used in each state and whether the state publicly reports participation and performance for students with disabilities on each test. It also provides participation data when available and data on the performance gap between students with disabilities and the total population. Only 16 states reported participation and performance results for students with disabilities on all of their tests, although 15 additional states provided this data for some tests. Most states that reported disaggregated performance results also reported disaggregated participation results. Six recommendations include: (1) provide data no more than 6 months after test administration; (2) establish reporting practices consistent with the Individuals with Disabilities Education Act; and (3) report the number and percent of students with disabilities using accommodations. Appendices provide the sample verification table and disaggregated participation information. (DB)