With the development of the PA KEI completed and a number of school districts using this tool and willing to contribute to its further development, OCDEL commissioned researchers at American Institutes for Research (AIR) and the University of Pennsylvania (Penn) to conduct a rigorous validity study of the PA KEI in its current form as part of its ongoing continuous improvement strategy. This study sought to determine (a) the scientifically based dimensions of children's competency measured by the PA KEI, (b) the evidence-supported uses of the PA KEI, and (c) evidence pointing to potential areas in which ongoing improvements of the PA KEI would enhance its use. (author abstract)