In this paper we evaluate the potential for California’s so-called civil grand juries to detect substandard prison conditions and maltreatment of inmates and make recommendations for improvement. We describe relevant reports by grand juries between 2007-17 and evaluate the effectiveness of these in improving conditions in a representative sample of counties. We conclude that the civil grand jury is a potentially effective tool for oversight but its effectiveness is hampered by competing duties, variable investigative methodologies, and lack of clear objectives for performance of their statutory duties
