There is a huge irony in the New York City Schools’ announcement that it is changing part of the admission exam to its gifted and talented program because of test preparation companies. To understand why, recall Campbell’s Law, formulated in 1975 by Donald C. Campbell. A test of giftedness should, strictly speaking, be used simply to decide whether someone is gifted. Unfortunately, that is not the use to which the City Schools’ test is being put: it is also being used for “social decision-making”—as an admission test. As soon as a test’s purpose goes from diagnosis to social decision-making, it becomes subject to “corruption pressure.” The New York Times article hyperlinked above reports precisely such corruption pressure in the form of test-prepped four-year-olds so expert in test-giftedness that one of them can brush off the psychologist’s oral instructions with a dismissive “I know what to do.”
Well, my dear, so do your teachers; and that leads to the irony. The City Schools are not shelving, or even changing, the tests and formulae used as the basis for “value-added metrics” even though they entail social decision-making that can denature the “education” students receive or unjustifiably break the careers of the teachers “evaluated.” This in spite of (or because of!) the City Schools’ spending more for books of test preparation than for any other kind. It is ironic that a school system objects to the hijacking of tests by test-preparation companies at the same time that the corruption pressures spawned by its own “evaluations” turn whole schools, whole districts, into a giant test preparation company. I smell a RAT.
 “The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures, and the more apt it will be to distort or corrupt the social processes it is intended to monitor.”
 RAce to the Top, which mandates testing and value-added metrics as a qualification for its funds.