Students stay longer at New York City charter schools than at traditional public elementary schools, according to an Independent Budget Office study.

The study found that 70 percent of kids who entered charter kindergartens in September 2008 were attending the same school three years later, compared with 61 percent of public-school kids.

The researchers said that’s significant because moving from school to school hurts student performance.

Kids who remained in either kind of school did significantly better on third-grade math and reading tests than those who moved, according to the study released Thursday.

For example, 74 percent of those who remained in their charter school met or exceeded the math proficiency standard, compared with 49 percent who transferred.