Law Matters -- Less Than We Thought

40 Pages Posted: 20 Aug 2019

See all articles by Daniel M. Klerman

Daniel M. Klerman

University of Southern California Gould School of Law

Holger Spamann

Harvard Law School; ECGI

Date Written: August 19, 2019


In a pre-registered 2×2×2 factorial between-subject randomized lab experiment with 61 federal judges, we test if the law influences judicial decisions, if it does so more under a rule than under a standard, and how its influence compares to that of legally irrelevant sympathies. The judges were given realistic materials and a relatively long period of time (50 minutes) to decide a run-of-the-mill auto accident case. We find weak evidence for the law effect, stronger evidence that rules constrain more than standards, and no evidence of a sympathy effect. Unexpectedly, we find that judges were more likely to choose the law that fully compensates an injured plaintiff.

Keywords: judicial decisionmaking, experiment, rules versus standards, choice of law, conflict of law

JEL Classification: K00, K13, K40, K41

Suggested Citation

Klerman, Daniel M. and Spamann, Holger, Law Matters -- Less Than We Thought (August 19, 2019). USC CLASS Research Paper No. CLASS19-26, USC Law Legal Studies Paper No. 19-26, Available at SSRN: or

Daniel M. Klerman (Contact Author)

University of Southern California Gould School of Law ( email )

699 Exposition Boulevard
Los Angeles, CA 90089
United States
213-740-7973 (Phone)
213-740-5502 (Fax)


Holger Spamann

Harvard Law School ( email )

Cambridge, MA 02138
United States

ECGI ( email )

c/o the Royal Academies of Belgium
Rue Ducale 1 Hertogsstraat
1000 Brussels

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