Graduating from one school to another for sixth grade is typical, but the arrangement is not ideal for student achievement.

That’s according to a new study the compared the varied pathways that city students took to eighth grade from 1995 to 2002. The report, “The Path Not Taken: How Does School Organization Affect Eighth-Grade Achievement?”, was just released in the Summer 2011 issue of the journal Educational Evaluation and Policy Analysis.

Led by Amy Ellen Schwartz and Leanna Stiefel at New York University, the researchers looked at “grade span paths,” or the grade configurations of the schools that students attended on their way to eighth grade. With more than 900 elementary and middle schools, New York City boasted 28 different grade span paths during the period studied, the report notes, making it an ideal laboratory to study effects of school organization on student achievement.

Looking at eighth-grade state and city test scores and controlling for a host of other factors, the researchers found that students who moved from K-4 schools to 5-8 schools and students who remained enrolled in a single K-8 school outperformed students who moved to middle school in sixth grade. But they couldn’t conclude why those arrangements were more successful.

“Our results suggest that changing school less frequently, changing schools at an earlier grade, a smaller size of the within-school cohort, and the stability of students’ peer cohorts are the most likely explanations for these positive performance differences,” the researchers write.

And they caution that simply changing all schools to the models they deemed most effective wouldn’t necessarily produce uniformly improved student achievement.

Since the study’s data was generated, the city began to manage middle schools admissions centrally, and charter schools became more prevalent. Many charter schools follow the grade arrangements that the researchers conclude are most conducive to student achievement.