Use of observational measures to monitor preschool quality is growing rapidly. This paper examined the degree of agreement between local and research rater teams using an observational measure of preschool classroom quality, and the extent to which ratings predicted gains in children’s literacy, math, and self-regulation skills. Both rating teams observed 85 classrooms using the Pre-K CLASS and 820 children (average age = 52.6 months, SD = 3.6 months) were directly assessed in the fall and spring. Results indicated moderate correlations between local and research teams’ scores, ranging from r = .19 to .40. Both teams’ scores significantly predicted child gains, although patterns of association differed. Results are discussed in the context of policies that require observational measures at scale.