What is the Coase theorem?

The proposition that, absent transaction costs and with clear property rights, private bargaining yields efficient outcomes regardless of how legal liability is initially assigned.

Is law and economics part of law or economics?

Both — it is an interdisciplinary field applying economic methods to legal questions, influential in law schools and economics departments alike.

Law and Economics

Law and economics applies economic analysis to legal rules and institutions — examining how laws shape incentives and how legal rules can be designed for efficiency.

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Scope

The field (JEL category K) covers the economic analysis of property, contracts, torts, crime and punishment, litigation and regulation, treating legal rules as devices that allocate resources and shape behaviour.

Sub-topics

Core questions

How do legal rules affect economic incentives and behaviour?
What allocation of legal entitlements is efficient?
How should liability and punishment be designed?
How do transaction costs shape the effects of law?
When do legal rules promote or hinder efficiency?

Key concepts

Coase theorem
Transaction costs
Property rights
Efficient liability
Deterrence
Externalities
Litigation incentives

Key theories

The Coase theorem: Coase showed that with well-defined property rights and zero transaction costs, parties bargain to efficient outcomes regardless of liability assignment — and that transaction costs are what make legal rules matter.
Economics of crime: Becker modelled crime as a rational choice responsive to expected costs, founding the economic analysis of deterrence and punishment.
Accident law and efficient liability: Calabresi analysed tort law as a means of minimizing the social costs of accidents, and Posner systematized the efficiency analysis of law across fields.

History

Law and economics emerged at Chicago and Yale in the 1960s-70s, founded by Coase's analysis of social cost (1960), Becker's economics of crime (1968), and Calabresi's and Posner's systematic application of economic reasoning to law, becoming one of the most influential movements in legal scholarship.

Debates

Should law maximize efficiency?: The efficiency norm at the heart of law and economics is contested by accounts emphasizing justice, rights, and distribution.
How realistic is rational deterrence?: The rational-actor model of crime is debated against behavioural and sociological accounts.

Key figures

Ronald Coase
Gary Becker
Guido Calabresi
Richard Posner

Seminal works

coase-1960
becker-1968
calabresi-1970
posner-1973

Frequently asked questions

What is the Coase theorem?: The proposition that, absent transaction costs and with clear property rights, private bargaining yields efficient outcomes regardless of how legal liability is initially assigned.
Is law and economics part of law or economics?: Both — it is an interdisciplinary field applying economic methods to legal questions, influential in law schools and economics departments alike.