Analysis: Schools With the Highest Grad Rates Have the Lowest Student Mobility. What Does That Say About This Measure of School Success?

Educators, policymakers, and parents often assume graduation rates are the best indicators of school performance. U.S. News & World Report, for example, ranks the nation’s high schools largely based on their reported four-year cohort graduation rates. But these rankings miss a critical point: the relationship between mobility and graduating.

The crucial distinction between the so-called best and worst schools is the vast difference in student mobility — the rate at which students enter or leave a school. When mobility is factored into graduation rates, the simple black-and-white comparison becomes a complex shade of gray.

The four-year cohort graduation rate calculation includes only at the final status of a student’s senior year to determine if he or she was successful in high school. If the student fails to graduate on time, only the last school he or she attended is rated poorly for the student’s “failure.” The calculation does not factor in whether the student may have come to the school credit-deficient or already failing, with no chance to graduate in June of senior year.

Picture an 11th-grader entering a new school with fewer than average credits and reading and math skills in the 20th percentile. While at the new school, those skills improve to the 50th percentile and the student passes all classes. But because of the earlier credit deficiency, the students must take another semester of courses before graduating. The system will say that both the student and the most recent school failed, despite the improvement and ultimate graduation, and the student’s previous school — where the student had fallen behind — “succeeded.”

A strong correlation between school mobility and graduation rates has been well documented in Oregon, Ohio, and Idaho. The top 20 schools in Oregon, for example, have an average graduation rate of 93.26 percent and an average mobility rate of 10.50 percent. The bottom 20 schools have an average graduation rate of 46.46 percent and an average mobility rate of 40.77 percent. That means those schools deemed the worst have a mobility rate nearly four times higher than those schools deemed the best.

The current four-year cohort graduation rate metric was created in 2005, when the National Governors Association formed a compact that was later endorsed by the governors of all 50 states, who embraced this calculation of success. The association’s task force submitted the compact with a commitment to consider the “treatment of students whose graduation is delayed due to issues beyond a state’s or school’s control” — a commitment their metric never upheld.

Under this metric, many of the “best” schools have very low mobility. The students who start in grade 9 are mostly the same students who finish in grade 12. That doesn’t hold true in the “worst” schools because most have students transferring in and out during their four years of high school.

One solution is to calculate how many students in grades 9-12 accumulated an adequate number of credits during the year. This holds all schools responsible for every student, every year, and creates a more accurate measurement of school success. Schools with high mobility often have many credit-deficient students (many of them from their first day at that school) who are unlikely to graduate on time. Holding schools accountable for credit accumulation ensures attention is given to the problem before it is too late.

Rather than relying so heavily on simple four-year graduation rates as a means of identifying the “best” and “worst” high schools, we need to understand the limitations of the metric fully. Getting students across the graduation stage is the goal for high schools, but that measure is often more indicative of the types of students the school serves than of the school’s success or failure. It’s time we rethink this measurement tool.

Steve Werlein is head of school at Oregon Virtual Academy. Mary Gifford is senior vice president of academic policy and external relations for K12 Inc.

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