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February 7, 2018

"Event dependence in U.S. executions"

The title of this post is the title of this new empirical paper authored by Frank Baumgartner, Janet M. Box-Steffensmeier and Benjamin Campbell.  Here is the abstract:

Since 1976, the United States has seen over 1,400 judicial executions, and these have been highly concentrated in only a few states and counties.  The number of executions across counties appears to fit a stretched distribution.  These distributions are typically reflective of self-reinforcing processes where the probability of observing an event increases for each previous event.  To examine these processes, we employ two-pronged empirical strategy.  First, we utilize bootstrapped Kolmogorov-Smirnov tests to determine whether the pattern of executions reflect a stretched distribution, and confirm that they do. Second, we test for event-dependence using the Conditional Frailty Model.

Our tests estimate the monthly hazard of an execution in a given county, accounting for the number of previous executions, homicides, poverty, and population demographics. Controlling for other factors, we find that the number of prior executions in a county increases the probability of the next execution and accelerates its timing.  Once a jurisdiction goes down a given path, the path becomes self-reinforcing, causing the counties to separate out into those never executing (the vast majority of counties) and those which use the punishment frequently.  This finding is of great legal and normative concern, and ultimately, may not be consistent with the equal protection clause of the U.S. Constitution.

February 7, 2018 at 10:42 AM | Permalink


The Equal Protection Clause may also require that other jurisdictions catch up to the high death penalty ones. The sole bias found in the death penalty has been the under valuation of black murder victims.

Posted by: David Behar | Feb 7, 2018 12:10:01 PM

Some of this is putting a pseudo-science gloss on the obvious. As with anything else, there is a learning curve. A surgeon who has never performed open heart surgery is unlikely to start performing open heart surgeries tomorrow. On the other hand, a surgeon who regular performs open heart surgeries is very likely to be performing open heart surgeries in the near future. Similarly, an office with no experience of trying a capital case is going to be somewhat more reluctant to pursue the death penalty than an office that is comfortable with the complexities of capital litigation.

Posted by: tmm | Feb 7, 2018 4:24:29 PM

TMM. Excellent point.

Posted by: David Behar | Feb 7, 2018 8:16:22 PM

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