In this chapter, we report on the analyses focusing on both quality thresholds and quality features. First, we address questions about quality thresholds, using two analytic approaches. The analyses ask whether there is evidence suggesting thresholds in the association between a specific quality measure and a specific child outcome. Second, we extend these analyses to ask whether each child outcome is more strongly related to global quality measures or to quality measures that measure teacher-child interactions or quality of instruction in a given content area. The research to date provides the basis for the articulation of two hypotheses related to quality thresholds and features: (1) the quality of ECE is a stronger predictor of residualized gains in child outcomes in classrooms with higher quality than in classrooms with lower quality and (2) more specific measures of quality are stronger predictors of residualized gains in child outcomes than are global measures. We turn now to analyses intended to address these hypotheses by using data from several data sets. (author abstract)