JEFFERSON CITY, Mo. — Missouri’s only unaccredited public school district won an upgrade Friday following improvement in student achievement and graduation rates.

The State Board of Education decided to grant provisional accreditation to the Normandy school system in suburban St. Louis, effective Jan. 2. The school district has been unaccredited since September 2012 and has been run by a state-appointed board for the past several years.

As an unaccredited district, state law has required Normandy to pay tuition for students who choose to transfer to better-performing schools in the area. Provisional accreditation means that could end, though state officials said Friday that neighboring school districts have agreed to continue teaching the roughly 600 transfer students from Normandy through the end of the current school year. Some transfer students may be allowed to remain even longer at their new schools, if they are nearing graduation from high school or middle school.

Missouri has 511 accredited school districts.

Normandy will join five others as provisionally accredited — the rural Calhoun district in west-central Missouri; Hickman Mills in the Kansas City area; the Kansas City district; Hayti in southeast Missouri; and Riverview Gardens in suburban St. Louis.

Provisionally accredited districts are subject to more state monitoring than fully accredited schools and must work with a regional school improvement team.

Missouri rates school district performance on a scale from 0 to 100. Schools typically must score at least 70 to be fully accredited and above 50 to be provisionally accredited, though the final decision rests with the state board. Normandy had received a mere 7 points in its 2014 rating. It received a score of 54.6 in 2016 and 62.5 this year.

Earlier this year, Normandy voters approved a $23 million bond issue that will fund a new early childhood center and improvements to science, technology and library facilities at its elementary schools. The school board also recently decided to close its middle school by 2019 and instead expand its elementary schools to serve students in grade K-8, following a model used by some charter and private schools.

Normandy Superintendent Charles Pearson said gaining provisional accreditation accomplishes a “short-term goal.”

“The long-term goal is that we truly would create a quality system,” Pearson said at the state board meeting.