Any objective rule that decides who qualifies for a social programme will exclude some people who deserve help and include some who do not.
Charles Murray stated it as the first of three laws of social programmes in Losing Ground (1984), his study of American welfare policy from 1950 to 1980. Eligibility has to be defined by rules that can be checked, such as income thresholds, and any line drawn through a continuous population leaves people just above it who resemble those just below.
In practice
- A housing grant capped at a fixed income excludes a family earning a few pounds more than one that qualifies.
- A scholarship awarded on a test score passes over a candidate one mark short who was stronger in every other respect.
- Possible explanations
- One explanation is that need is continuous while rules are discrete, so any threshold creates arbitrary cases at its edge. Another is that the information needed to judge each case individually is expensive or unavailable.
- In its favour
- Close to a logical consequence of rule-based eligibility, and accepted by designers of benefit systems across the political spectrum, who respond with tapered withdrawal and appeals.
- Against it
- Critics accept the point but dispute the conclusion Murray drew from it, arguing that imperfect targeting calls for better design rather than fewer programmes. Discretionary systems avoid rigid thresholds but introduce bias of their own.
- Standing
- Compare Murray's law of unintended rewards and Goodhart's law.
- Subject
- Economics & Incentives
- Essay
- The theories behind every argument about money