This commentary highlights the work of the Collaborative for Building After-School Systems (CBASS), a collaborative of mature, city and county-wide nonprofit OST intermediaries, to develop and adopt common youth-, program- and system-level measures that are easy and cost-effective for local systems to implement. By agreeing to adopt and publicly report against a common set of outcomes, CBASS hopes to spark more efforts to use common measures to assess program productivity and success, hold providers accountable to quality, demonstrate after-school's contribution to the successful development of children and youth and contribute to system-building and sustainability. (Contains 2 figures and a list of Resources.)