Every Hour Counts, formerly the Collaborative for Building After-School Systems (CBASS), commissioned this literature review as it is in the process of revising its 2008 measurement framework to reflect changes in policy, practice, and research. The purpose of this literature review is to define key elements, processes, and outcomes of afterschool and expanded learning systems. The revised Every Hour Counts Measurement Framework consists of 8 elements and 28 outcomes, across three levels of organization: system, program, and youth (CBASS, 2012). The review is organized by those tiers, starting with the system level and continuing through the program and youth levels. The review aims to address the following questions at each level of the expanded learning system: System level: What are promising practices employed by systems that may support program-level quality? Program level: What are the best program practices that may ultimately promote positive youth outcomes? Youth level: Which youth outcomes can programs influence and which ultimately lead to academic and life success? (author abstract)