Similar to indices used by other states, the API is a composite measure of student achievement ranging between 200 and 1000. The goal is an API of 800. Schools with APIs below 800 can meet their annual targets if they make up at least 5% of the difference between their API score and 800—akin to the school-level growth-to-proficiency model used in NCLB’s Safe Harbor provisions. While only California uses these exact measures, many states have adopted API-like techniques in their new NCLB-waiver accountability systems. We assessed the API (and year-to-year changes in API) as a measure of school performance, as well as a means of identifying low performing schools. we made several suggestions for revising API. Our goal was to not only propose changes that could be implemented relatively easily, but also those that would markedly improve the identification of schools in need of intervention and/or additional support.