We develop a unied empirical framework for child development which nests the key features of two previously parallel research programs, the Child Development literature and the Education Production Function literature. Our framework allows for mis-measured cognitive and non-cognitive skills, classroom effects, parental in uences, and complementarities. Although both are important, we estimate that differential parental investments are the more important source of end-of-kindergarten inequality than classroom quality. Quality classrooms have a larger effect on children entering kindergarten with skill decits. Our estimated model replicates out-of-sample patterns by excluded race and family income variables and experimental results from the Tennessee STAR experiment.