More than half of teachers in city middle schools left their schools within three years, and most left teaching altogether, according to a new study that offers little insight about how to stem the exodus.

The study was presented yesterday at the Association for Public Policy Analysis and Management’s fall meeting, as part of a panel on teacher turnover. Will Marinell, a member of the Research Alliance, the independent body of researchers given access to city Department of Education data, and Teachers College professor Aaron Pallas conducted the analysis.

Mining data about teachers and their paths within the school system, the researchers found that 55 percent of middle school teachers leave their school within three years, higher than in elementary and high schools. They also found that their decision to leave was likely influenced more by their individual characteristics, such as their commute time and race, than by anything about their school.

According to the analysis, teachers are more likely to stay in their schools when students disproportionately share their race. In Manhattan, two-thirds of middle school teachers left within three years, the highest exit rate of any borough. Middle school teachers are more likely to consider leaving their school when they have a long commute or are required to teach a new subject. And teachers in schools that suspend many students are more likely to consider finding a new job.

“These rates of turnover are likely to make it challenging for middle school principals, and the teachers who remain in their schools, to establish organizational norms and a shared vision for their schools’ teaching and learning environment,” the study concludes.

That’s bad news for Schools Chancellor Dennis Walcott, who recently announced a major initiative to improve the quality of the city’s middle schools.

One component of the plan is to recruit new principals and teachers to struggling middle schools. Here the study offers some advice:

For instance, incentives and reforms that reduce teachers’ commuting times may be a promising approach for reducing turnover. Similarly, given how much higher the odds of considering leaving one’s school are among teachers who reported teaching a new subject area, principals might be well advised to make every attempt possible to resolve staffing challenges in ways that don’t require assigning teachers to new subject areas.

But tinkering with policies is unlikely to shift the turnover trends that are already established, the study concludes.

“Taken together, the historic observed rates of turnover among new-to-school teachers … and the anticipated rates of turnover among all current teachers … suggest that teacher turnover is likely to be an enduring characteristics [sic] of New York City middle schools in the years to come.”