The MetroWest Economic Research Center (MERC) at Framingham State College annually determines K-12 public school enrollment for several substate regions. Enrollments are calculated for kindergarten through grade 12 students using the annual state student census conducted on October 1 of each year. Included in the data are all public school students in regular education, special education, ESL (English Language Learners), regional schools and regional vocational high schools. The total enrollment figures also include enrollments in any charter schools in each region.

In many communities kindergarten enrollment typically increases around 10% upon entry into first grade; on some of the graphs this is noted with as asterisk* next to the K.

The Massachusetts Department of Elementary and Secondary Education implemented a student enrollment database, the Student Information Management System (S.I.M.S.) in 2000. The MERC K-12 data are obtained from both the October 2007 S.I.M.S. student census and information provided directly to MERC by the local school districts.