Studying Nonobviousness

53 Pages Posted: 6 Apr 2021 Last revised: 26 May 2021

See all articles by Jason Rantanen

Jason Rantanen

University of Iowa - College of Law

Lindsay Kriz

University of Iowa, College of Law, Students

Abigail Matthews

State University of New York at Buffalo

Date Written: April 2, 2021


Numerous scholars have observed that an empirical study is only valid to the extent it is reliable. Yet assessments of the reliability of empirical legal studies are rare. The closest most scholarship comes is to compare the results of their studies to those of others. As a result, in many legal fields, including intellectual property law, scholars lack a grounded understanding of how valid or reliable empirical legal studies really are.

This article examines the reliability of empirical studies of judicial decisions by closely comparing two recent studies of the patent law doctrine of nonobviousness. We find that these studies provide robust results despite differences in the cases selected for inclusion in each dataset. However, the amount of agreement varied for some data fields more than others. Particularly, there was more inter-study variability for fields that examined judicial reasoning than fields for decision outcomes. This finding provides some validation for the use of macro-level studies of judicial decisionmaking. To the best of our knowledge, this is the first analysis to directly compare the actual coding (as opposed to just the outcomes) of two different studies examining the same patent law doctrine.

Building on the existing data, we also make an original contribution to the literature on nonobviousness by extending the period encompassed by the earlier studies to the present. In contrast with studies examining the immediate period after the Supreme Court’s decision in KSR v. Teleflex, we find (1) a substantial decline in the number of § 103 district court cases appealed to the Federal Circuit, (2) a higher rate at which the patent is deemed nonobvious, and (3) a high affirmance rate for district court determinations of both “obvious” and “nonobvious.”

Keywords: patent, empirical, Federal Courts

Suggested Citation

Rantanen, Jason and Kriz, Lindsay and Matthews, Abigail, Studying Nonobviousness (April 2, 2021). Hastings Law Journal, Forthcoming, U Iowa Legal Studies Research Paper No. 2021-21, Available at SSRN:

Jason Rantanen (Contact Author)

University of Iowa - College of Law ( email )

Melrose and Byington
Iowa City, IA 52242
United States

Lindsay Kriz

University of Iowa, College of Law, Students ( email )

Iowa City, IA
United States

Abigail Matthews

State University of New York at Buffalo ( email )

Amherst, NY 14260
United States


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