Parol Evidence Rules and the Mechanics of Choice

Theoretical Inquiries in Law, Vol. 20, Pp. 457-486 (2019)

31 Pages Posted: 1 Apr 2018 Last revised: 18 Jul 2019

See all articles by Gregory Klass

Gregory Klass

Georgetown University Law Center

Date Written: July 11, 2019


Scholars have to date paid relatively little attention to the rules for deciding when a writing is integrated. These integration rules, however, are as dark and full of subtle difficulties as are other parts of parol evidence rules. As a way of thinking about Hanoch Dagan and Michael Heller’s The Choice Theory of Contracts, this Article suggests we would do better with tailored integration rules for two transaction types. In negotiated contracts between firms, courts should apply a hard express integration rule, requiring firms to say when they intend a writing to be integrated. In consumer contracts, standard terms should automatically be integrated against consumerside communications, and never integrated against a business’s communications. The argument for each rule rests on the ways parties make and express contractual choices in these types of transactions. Whereas Dagan and Heller emphasize the different values at stake in different spheres of contracting, differences among parties’ capacities for choice — or the “mechanics of choice” — are at least as important.

Keywords: contract law, parol evidence rule, consumer contracts, contract theory

Suggested Citation

Klass, Gregory, Parol Evidence Rules and the Mechanics of Choice (July 11, 2019). Theoretical Inquiries in Law, Vol. 20, Pp. 457-486 (2019). Available at SSRN:

Gregory Klass (Contact Author)

Georgetown University Law Center ( email )

600 New Jersey Avenue, NW
Washington, DC 20001
United States


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