Private Law Theory

ABSTRACT
Contra proferentem, the enduring maxim that directs courts to construe an ambiguity in a contract against its drafter, appears simple on its face. Although it might be best known as a fundamental principle of insurance law, contra proferentem figures in courts’ interpretation of a range of contract types. As an interpretive rule of thumb that parties can easily override with a simple contract provision, the doctrine and its boilerplate antidote seem to offer a straightforward means to facilitate private ordering – a central goal of contract law.

However, neither courts’ application of the doctrine in the caselaw nor its treatment by contract drafters proves clear-cut. Courts persist in invoking the doctrine but fail to apply it consistent or clarifying ways. Is this a tool of equity or efficiency? Is it a tie breaker of last resort or a first-order rule? Legal thinkers have debated the rationale behind the doctrine, with no single explanation providing a justification in every contract context. Thus, given the conceptual murkiness of the doctrine, and the risk that it may be enforced in unpredictable ways, we would expect commercial parties to make regular use of simple-to-implement provisions specifying the inapplicability of the doctrine. Notably, however, surprisingly little data has been available concerning how courts treat contra proferentem and whether commercial parties choose to opt out of the rule.

This project provides empirical data that challenge some conventional wisdom around the operation of contra proferentem. In doing so, it offers a theoretical and normative intervention, raising questions about the efficacy of the doctrine as a tool of private ordering. This study uses close reading of three paradigmatic jurisdictions: California, New York, and Delaware, and provides macro data on these and other states as well as federal courts. The findings fly in the face of expectations that the doctrine primarily operates as a principle of equity. In addition, they suggest that contra proferentem often operates as an opaque discretionary tool in commercial contracts. The doctrine’s unpredictability, in turn, makes the relative dearth of opt-out boilerplate in sophisticated-party contracts, which this study also reveals, even more surprising.

In addition to providing novel data, this Article offers an explanation for the persistence and murkiness of the doctrine of contra proferentem. It suggests the doctrine endures because it aims to serve different objectives in different contract contexts; as an equitable tool in the context of adhesive consumer contracts and as a last-resort tie breaker in commercial contracts. Yet, the failure of courts to police these boundaries leads to the blurring of the doctrine in the caselaw, an impediment to predictability and transparency essential to the private law. Moreover, it calls into question a premise of private ordering – the ability of sophisticated actors to use contracts to effectuate their preferences. As such, this study demonstrates the challenge to private ordering that results from a confluence of sticky contract doctrine and sticky contract gaps, threatening to undermine the predictability and efficacy of the common law for all.

Ghodoosi, Farshad and Kastner, Tal, Against the Drafter: An Empirical and Theoretical Analysis of the Doctrine of Contra Proferentem (June 25, 2025), Rutgers Law School Research Paper Forthcoming; Fordham Law Review (forthcoming, 2026).