Stressing their commitment to increasing test scores and graduation rates, New Haven officials announced the city’s second year of school tiering in a Monday press release.

The “vast majority” of schools have shown improvement, according to the release. New Haven Public Schools Superintendent Reggie Mayo cited the city’s ongoing school reform campaign as a factor in the district’s progress.

“The tiering shows that our schools have the momentum of sustained growth over the last few years, and that we are making continuing to make good progress to our school reform goals,” Mayo said. “We talk a great deal about growth, and that is what we are seeing in all key measures and in virtually all of our schools”

Ten of 12 New Haven high schools got more students on track to graduate following the implementation of tiers, while nine schools increased their graduation rate. In K-8 schools, nearly 80 percent increased the proportion of students performing at the target level.

School tiering is “the annual process in New Haven’s school reform effort, by which the different schools are categorized according to the performance of students,” according to the release. Schools in Tier I, the highest ranking, have consistently high student performance, whereas Tier II schools offer average student achievement and Tier III schools score poorly on student achievement. Tier III schools are subject to district intervention and requirements that Tier I and Tier II schools are not.