Article
A Tale of Two Studies: Revisiting the Unintended Effects of Staggered Legal Changes
Journal of Legal Studies
(2025)
Abstract
Post-2003 methodological innovations in causal inference suggest that many older studies investigating
the unintended e ects of legal changes need reappraisal. In particular, new Di fference-in-Di fference
estimators have been recently proposed in settings with staggered adoption that allow for treatment e ect
heterogeneity across groups and dynamic treatment e ects that may grow or dissipate over time. These
are common to most legal changes occurring at the state level in the U.S. We provide a practitioner-
oriented overview of those methodological developments, followed by two empirical illustrations. We
first revisit the study by Klick and Stratmann (2003) which found that abortion legalization led to an
increase in sexually transmitted diseases. Second, we revisit the analysis by Marvell and Moody (2001)
claiming that three strike laws caused an increase in homicides. While we find that the conclusions of
the second study are robust, we show that some of the conclusions of the first one are sensitive to the
new methodological developments.
Disciplines
Publication Date
Winter 2025
Citation Information
Stéphane Mechoulan, Juan Pantano and Isaac Rosenthal. "A Tale of Two Studies: Revisiting the Unintended Effects of Staggered Legal Changes" Journal of Legal Studies (2025) Available at: http://works.bepress.com/stephane_mechoulan/26/