It is a fact, that the quality of school's can greatly influence home values in any area. As a local expert, I can connect you with a variety of resources that will help you evaluate area schools. What exactly is the Academic Performance Index (API); it is a measurement of academic performance and progress of individual schools in California, United States. It is one of the main components of the Public Schools Accountability Act passed by the California legislature in 1999. API scores ranges from a low of 200 to a high of 1000.