The Measuring What Matters Performance Assessment Collaborative (PAC) is using competency-based professional learning approaches to support the use of high quality performance based assessments. The districts in the PAC, a subset of the Large Countrywide and Suburban District Consortium, are working together to establish common quality criteria for performance based assessments, to share best practices for professional learning, and to increase the number of teachers who have the knowledge and skills to incorporate performance based assessment into curriculum and instruction.