Abstract:Over the span of ten years, a National Science Foundation-funded partnership effort has collected and analyzed multiple forms of evidence, both direct and indirect, about improved teaching of mathematics within Rapid City Area Schools. This article describes the project's impact on K-12 teaching and factors contributing to that impact. The authors argue that improvements in teaching are attributable largely to a robust infrastructure established to support teacher growth. Direct evidence includes classroom observations conducted by the project's external evaluation team. Indirect evidence exists in the form of data on student outcomes: achievement on the state's multiple-choice accountability measure and achievement on project-administered performance assessments.Keywords: (K-12 mathematics education, teacher professional development, partnership, systemic reform)Project PRIME (Promoting Reflective Inquiry in Mathematics Education] began in 2002 with funding from the National Science Foundation (NSF]. A member of the initial cohort of NSF-funded Math and Science Partnership programs, PRIME was originally funded for five years. The award period has been extended several times and is now slated to conclude in 2013,11 years after its inception. Project PRIME has been working to improve the teaching and learning of K-12 mathematics within Rapid City Area Schools, South Dakota's second largest school district, and to improve the preparation of teachers at Black Hills State University, South Dakota's largest producer of teacher education majors. Project partners include Rapid City Area Schools (RCAS), Black Hills State University (BHSU], Technology and Innovation in Education (TIE], a nonprofit education service provider, and Inverness Research Associates, the external evaluator.Definition of Effective TeachingKey elements of effective mathematics teaching as defined by Project PRIME include:* Providing students with rich, meaningful, challenging mathematical tasks;* Focusing on big mathematical ideas and on connections among them;* Creating a safe and productive classroom culture ~ one that fosters a community of learning;* Paying attention to conceptual understanding, procedural fluency, student discourse, mathematical representation, and student dispositions; and* Drawing from a depth of pedagogical content knowledge to recognize patterns of student thinking, anticipate and diagnose misconceptions, and guide the learner in productive directions, especially through asking questions.PRIME has arrived at these key elements by drawing from the mathematics education literature. Resources used early within the project to develop a common vision among the project's leadership team, district math teacher leaders, building principals, university faculty, and other project staff included Adding It Up (Kilpatrick, Swafford, & Findell, 2001) and Making Sense: Teaching and Learning Mathematics with Understanding (Hiebert et al., 1997).District ProfileRapid City Area Schools includes 15 elementary schools (kindergarten through grade 5), 5 middle schools (grades 6 through 8), and 3 high schools (grades 9 through 12). It employs approximately 450 teachers of mathematics (including elementary and special education teachers), and it has a K-12 enrollment of approximately 13,000 students. Thirty-seven percent of students qualify for free or reduced-price lunch, and 24% are non-White (15% American Indian, 7% other non-White, 2% two or more races). Rapid City represents the largest off-reservation population of American Indian students in South Dakota.Project GoalsPRIME'S two overarching goals are: 1) to improve student achievement for all K-12 students within Rapid City Area Schools, and 2) to increase and sustain the quality of K-12 teachers of mathematics. Central to goal one of serving all students is a commitment to educational equity, seeking in particular to meet the needs of American Indian students and those who are economically disadvantaged. …