Law and economics applies the tools of microeconomic theory to legal rules and institutions. Its core claim is that legal rules create incentives, and people respond to incentives. The proper criterion for evaluating a legal rule is therefore its efficiency — whether it maximizes social wealth or minimizes social cost — rather than its conformity to abstract principles of justice, fairness, or rights.
The intellectual origins lie in Ronald Coase’s “The Problem of Social Cost” (1960), which argued that in a world without transaction costs, legal rules don’t matter: parties will bargain to the efficient outcome regardless of how rights are initially assigned. Since transaction costs are never zero, legal rules do matter — and the efficient rule is the one that places the entitlement with the party who values it most, minimizing the need for costly bargaining. Guido Calabresi’s The Costs of Accidents (1970) applied economic reasoning to tort law, arguing that liability rules should be designed to minimize the sum of accident costs and accident-prevention costs.
Richard Posner’s Economic Analysis of Law (1973) generalized the approach across the entire legal system: property, contract, tort, criminal law, family law, constitutional law. Posner argued — controversially — that common law rules tend toward efficiency: judges, whatever their stated reasoning, reach outcomes that maximize social wealth. The claim is descriptive (this is what judges do) and normative (this is what judges should do). Posner later tempered the strongest version, but the framework became institutionally dominant in American legal academia by the 1980s.
The law and economics movement has real institutional power. Chicago School economics shaped antitrust law (relaxing scrutiny of mergers and monopolistic behavior), regulatory policy (preferring market mechanisms to command-and-control regulation), and judicial appointments (the Federalist Society, influenced by law and economics scholarship, has shaped U.S. federal court composition for decades). The academic framework became a political program.
Critiques and limitations
The efficiency criterion is the central target of criticism. Efficiency means maximizing total wealth — but says nothing about how that wealth is distributed. A rule that makes one person a billion dollars richer and a million people a dollar poorer is “efficient” by the standard measure (Kaldor-Hicks efficiency), even if the winners never actually compensate the losers. The neutrality that law and economics claims — we’re just measuring costs and benefits — conceals distributional choices that are fundamentally political.
The behavioral economics challenge, developed from the 1980s onward by Daniel Kahneman, Amos Tversky, and others, undermined the rational actor model on which law and economics depends. People don’t maximize utility in the way the models assume: they are loss-averse, present-biased, subject to framing effects, and systematically miscalibrate probabilities. If people don’t behave as rational maximizers, then predictions about how legal rules affect behavior — the core of the law and economics project — require empirical investigation rather than deduction from models.
From the left, critical legal scholars argue that law and economics naturalizes market logic — treating market outcomes as the baseline from which legal “intervention” departs, rather than recognizing that markets themselves are constructed by legal rules. There is no pre-legal market; there is only a market shaped by particular property, contract, tort, and regulatory rules. To evaluate those rules by their “market efficiency” is circular.
Key texts
- Ronald Coase, “The Problem of Social Cost” (1960)
- Guido Calabresi, The Costs of Accidents (1970)
- Richard Posner, Economic Analysis of Law (1973)
- Gary Becker, “Crime and Punishment: An Economic Approach” (1968)
See also
- Legal Realism — the tradition whose empirical orientation law and economics extended
- Critical Legal Studies — the movement that emerged partly in opposition to law and economics
- Contract — the legal form of market exchange
- Tort — the domain where economic analysis has been most influential
- Property — the legal institution economic analysis takes as foundational