Class Size in Michigan: Investigating the Risk of Being in Very Large Classes

September 2016
Brian Jacob, Susan Dynarski, CJ Libassi, Rene Crespin

The number of students in a classroom has long concerned parents, teachers, and policymakers. This aspect of a student’s educational experience has always seemed to be an important marker of school quality, and a long line of research has confirmed this intuition. However, a common proxy for class size, the student-teacher ratio (STR), leaves much to be desired. The student-teacher ratio expresses the number of full-time equivalent teachers (FTEs) in terms of the number of students to whom a teacher would be assigned if all teachers were in charge of the same number of students in a school or district. Specifically, the student-teacher ratio takes the number of students in a school or district and divides it by the number of teachers. Though federal statistics are careful to distinguish between class size and student-teacher ratios, families, policymakers, and casual observers would not be blamed for thinking the two are synonyms, given the frequency with which the two are treated as interchangeable in policy discourse and academic research.

Key findings

  1. The student-teacher ratio substantially understates the number of students per class in all core academic subjects in every grade level.
  2. Many students in Michigan, which has no legal cap on class size, find themselves in especially large classes. In 1st grade, nearly 1 in 20 students has a homeroom of 40 or more students; in 7th grade and 9th grade, more than 1 in 10 students has at least one core course of that size.
  3. Risk of large classes in Michigan is not evenly distributed across race, economic level, or urbanicity:
  • Black 9th graders are over three times as likely as their white peers to be in such large classes;
  • At every grade level, students receiving meal subsidies are 60 to 70 percent more likely to be in large classes than their peers not receiving subsidies;
  • Nearly one in four 9th graders in urban districts are in a class of 40 or more students, while only 1 in 50 students in rural districts find themselves in such classes.