From the MA Depeartment of Elementary & Secondary Education's Website:
All Massachusetts districts and schools with sufficient data are classified into one of five accountability and assistance levels, with the highest performing in Level 1 and lowest performing in Level 5. In general, a district is classified into the level of its lowest performing school, unless the district was classified into Level 4 or 5 as a result of action by the Board of Elementary and Secondary Education. Massachusetts uses the Progress and Performance Index (PPI) to assess the improvement of each district and school toward its own targets. The PPI combines information about narrowing proficiency gaps, growth, and graduation and dropout rates into a single number. All districts, schools, and student subgroups with sufficient data are assigned an annual PPI based on two years of data and a cumulative PPI between 0 and 100 based on three annual PPIs. For a district or school to be considered to be making progress toward narrowing proficiency gaps, the cumulative PPI for both the "all students" group and high needs students must be 75 or higher.
Due to shift from paper-based MCAS tests to online testing, most schools received a classification of "No Level" on their 2017 Accountability data.