In February 2007, First 5 LA contracted with Mathematica Policy Research, Inc. (MPR) and its subcontractors, Juarez and Associates, American Institutes for Research (AIR), and Berkeley Evaluation and Assessment Research (BEAR) Center, to conduct the First 5 LA/LAUP Universal Preschool Child Outcomes Study (UPCOS). The authors conducted the study in two phases. The spring 2007 pilot phase (Phase 1) examined the feasibility, reliability, and validity of selected child development measures in the large, culturally and linguistically diverse population of children served by LAUP programs. In early spring 2007, the authors selected a purposive sample of 418 4-year-olds enrolled in 14 LAUP programs. The children were predominantly Latino (60 percent), and 28 percent spoke primarily Spanish at home. Data collection included direct child assessments and a teacher interview encompassing ratings of children's behavior and development. The second phase of the study (fall 2007 and spring 2008) addressed the quality and overall implementation of LAUP programs, children's growth from fall to spring, and the relationships between family characteristics and children's development over time. After describing the characteristics of the representative sample of children and families, the authors report their findings related to the three broad questions this study addresses, which are described in more detail in Chapter II: (1) What is the overall level and range of quality in the implementation of LAUP/PoP center-based programs?; (2) How do children enrolled in LAUP/PoP center-based programs develop from fall to spring?; and (3) How are characteristics of children and families related to school readiness outcomes? In Chapter II, the authors describe the study methods used, including how they sampled programs and families; what child, parent, teacher, and classroom measures they used; what data collection procedures they followed; and what research questions the study was designed to address. In Chapter III, they present the results, beginning with descriptive data on programs, teachers, and classrooms, followed by descriptions of children and families. They then report what they learned about parents' involvement and satisfaction with the program. They conclude the results chapter with findings about the relationships between child and family characteristics and the children's school readiness outcomes. Chapter IV summarizes the findings and presents their assessment of their implications for programs and recommendations for future study. In the appendices, they provide details on the measures used, the routing procedure used for determining the language of assessment, what they learned about a new experimental observational measure of teacher-child interactions, and their report on the PoP programs. Appended are: (1) Measures Used in Phase 2 of the Universal Preschool Child Outcomes Study; (2) Procedures for Routing Children into the Most Appropriate Language for Assessment; (3) Tables of Results Presented in Chapter III; (4) Descriptive Results from the Pilot Study of the Language Interaction Snapshot (LISn); (5) Descriptive Information on LAUP Programs Participating in the Power of Preschool Demonstration Program; and (6) Development of a Respect for Differences Scale. Individual appendices contain references. Individual chapters contain footnotes. (Contains 98 tables, 24 figures and 4 boxes.) [For executive summary, "The Children of LAUP: Executive Summary of the First 5 LA Universal Preschool Child Outcomes Study," see ED533142.]