Due to a growing national focus on the importance of school readiness, more states are developing learning standards for their preschools and assessing children's progress toward those standards (Daily et al. 2012). The tools used to conduct these assessments range from teacher-administered checklists and observation rubrics to evaluations that children complete themselves using computer programs or other materials. Research supports the use of such varied tools to fully capture the cognitive and social-emotional development of young children. Indeed, using information from several sources that cover a range of domains is especially important for measuring the progress of children from diverse cultural and linguistic backgrounds (Howard 2011; Bandel et al. 2012). To learn more about teachers' use of multiple assessments, we examined program practices in a state-funded preschool in Milpitas Unified, a school district in northern California that had recently begun using a second assessment. Overall, we find that teachers may need a range of supports when given the opportunity to integrate a new assessment tool into their practice. Teachers generally value the information that comes from assessment. However, to act effectively on that information, they need opportunities for formal training, ongoing support from supervisors, and the chance to learn through collaboration with their colleagues--both within and across classrooms and grades. (author abstract)