Assessing the Impact of Planned Social Change
Campbell (1979) — Campbell's Law on corrupted social indicators
1979 essay arguing that quantitative social indicators used for decision-making become subject to corruption pressures and distort the processes they monitor.
Campbell, D. T. (1979). Assessing the impact of planned social change. Evaluation and Program Planning, 2(1), 67–90. (Also widely circulated as a standalone essay.)
Core claim (Campbell’s Law)
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.
Context: Program evaluation and policy — how organisations measure reform and reward movement on indicators. Parallel to Goodhart (1975) on monetary targeting; broader in social-science scope. Marilyn Strathern (1997) later popularised a one-line paraphrase often misattributed to Goodhart alone.
In this corpus
Mechanism for second-order risk in closed-loop control: once a declared sensor or comparator in an (A)DR hypothesis loop is tied to mandatory actuators and incentives, it becomes a target — see meta-loop control.