Campbells lov

Når en indikator brukes som grunnlag for beslutninger, vil den korrumpere og forvrenge det den var ment å måle.

In a paper entitled “Assessing the Impact of Planned Social Change,” American social scientist Donald T. Campbell described the effect of quantitative measurements on decision-making processes this way:

«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 and corrupt the social processes it is intended to monitor.»

Campbell used crime rate as an example in his paper.  He pointed out that a decrease in a city’s crime rate may not demonstrate a true reduction in the number of crimes that have been committed, but may simply reflect how the police force has changed procedures to lower the number. They may have decided, for example, to change which police encounters need to be formally recorded. They may also have downgraded some crimes to less serious classifications.