Why colleges’ “average class size” statistics are misleading — and how to fix them

  • Amherst College reports an average (mean) class size of 19.
  • Harvard University reports a median class size of 12.
  • Columbia University reports that 80% of classes have fewer than 20 students.
Mean class size example calculation
Mean class size formula
Frequency-weighted mean class size formula
Frequency-weighted mean class size calculation
Example distribution of student class size at Harvard University
Avg. class size vs. adjusted avg. class size
Avg. class size vs. % change from avg. class size to adj. avg. class size

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Kyle Giddon

Kyle Giddon

analytics, data, public policy | Cambridge, MA