Lake Wobegon effect hits USA Today

(by Howard Wainer)

Jack Gillum and Marisol Bello report on apparent cheating in the DC schools:

A USA TODAY investigation, based on documents and data secured under D.C.’s Freedom of Information Act, found that for the past three school years most of Noyes’ classrooms had extraordinarily high numbers of erasures on standardized tests. The consistent pattern was that wrong answers were erased and changed to right ones.

Noyes is one of 103 public schools here that have had erasure rates that surpassed D.C. averages at least once since 2008. That’s more than half of D.C. schools.

Erasures are detected by the same electronic scanners that CTB/McGraw-Hill, D.C.’s testing company, uses to score the tests. When test-takers change answers, they erase penciled-in bubble marks that leave behind a smudge; the machines tally the erasures as well as the new answers for each student. . . .

So, over the course of several years, more than half the schools have had greater than average erasure marks? During the same period, I would wager that about half the kids were above average height too.

Editor’s note: Overall the Gillum and Bello is excellent: they discuss the evidence and potential explanations in detail and also provide a lot of background information. But I agree with Howard that it’s not so surprising that more than half the schools have surpassed the average.