Since the reauthorization of the Individuals with Disabilities Education Act (IDEA) in 2004, U.S. state IDEA programs have been required to report annually on a set of performance indicators. Indicator 8 of the Part B State Performance Plan is the "percent of parents who report that schools facilitated parent involvement as a means of improving services and results for children with disabilities." The purpose of this study was to investigate whether changes over time in national and state-level performance on Indicator 8 provide evidence in support of the effectiveness of the accountability requirement related to parent involvement. Data were extracted from states' Annual Performance Reports and other publicly available documents. Findings indicated that national performance on Indicator 8 increased from 63% in 2006 to 76% in 2018. Within-state change in performance from 2014 to 2019 ranged from -13.47% to +42.50%, with several states indicating dramatic year-to-year changes in their reported performance. The findings raise important questions about the extent to which the indicator in its current form can support the dual purpose of holding states accountable for their facilitation of parents' involvement and supporting improvement efforts. Implications for both federal policy and state-level action are discussed.