Campbell’s law is defined by the following quote from Donald T. Campbell:
“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.”
In other words: the higher the stakes associated with a measure, the more likely it is that the measure is corrupt and in so doing that the system being measured becomes corrupt.
If you put high stakes against a school exam the more likely it is that people teach to get a high pass mark and in so doing teaching become corrupt.
If you put high stakes against a business measure the more likely it is that people manage to the measure, or even falsify the measure, and in so doing corrupt the business.
There are numerous places where you can see this being worked out historically; the more important question, though, is where is this happening today?
What effect does it have if you stop people’s benefits if they don’t fill out a defined number of job applications?
What effect does it have if you pay a traffic warden on the basis of the number of fines they manage to issue?
What effect does it have if you fine rail operators for late trains?
What effect does it have if you pay doctors on the basis of the number of appointments they complete?
I’m sure there are many, many more.
This little video does a really nice job of explaining Campbell’s Law:
Graham Chastney 