According to previous research, three point-of-service features—strong youth engagement, well-conceived and well-delivered content, and a conducive learning environment—lead to positive impacts in after-school settings, the ultimate gauge of quality. To assess quality at a program's point of service, researchers and program administrators should measure indicators of these three quality features. We argue that youth engagement should be the first of these indicators to be measured because it reflects both the content of program activities and the conditions of the learning environment. Next, content should be assessed to ensure that staff deliver a well-designed sequence of active tasks that are linked explicitly to the development of desired skills or competencies. Finally, assessing the learning environment can help explain whether youths' absorption of the content is inhibited by poor interactions, limited youth decision making, or unsafe conditions. In presenting and evaluating multiple measurement approaches, the authors argue that the most reliable measures are those collected from the agent (either youth or staff members) to whom the indicator is most directly tied. Engagement, for example, is an experience of the youth, content is delivered by staff members, and the learning environment, which is maintained by staff members and experienced by the youth, is tied to both agents. Findings from quality assessments should be used to feed an ongoing process of training, support, and content change aimed at quality improvement.