Comment on

Ashley RubinThe Declining Death Penalty in Eighteenth-Century

London?The Role of Ecological Fallacy in Lenience-Based Accounts

Dan KlermanConference on Empirical Legal Studies

October 25, 2013

Before 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 8,090 74% 1,243 15%

Other crimes 2,885 26% 212 7%

Total 10,975 1,455 13%

After 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 29,839 81% 2461 8%

Other crimes 6,811 19% 688 10%

Total 36,650 3149 9%

Theft is vast majority of prosecutionsSo decline in probability of death sentence for theft

Drives overall statisticsMasks increase in probability of sentence for other crimes

Relatively small change in case compositionIs it helpful to describe this as ecological fallacy? Contrast Simpson’s paradox

Before 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 8,000 80% 1600 20%

Other crimes 2,000 20% 200 10%

Total 10,000 1800 18%

After 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 2,000 20% 500 25%

Other crimes 8,000 80% 1200 15%

Total 10,000 1700 17%

Simpson’s Paradox(hypothetical data)

Before 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 8,090 74% 1,243 15%

Other crimes 2,885 26% 212 7%

Total 10,975 1,455 13%

After 1718 Prosecutions % of prosecutions

Death sentences

Probability of death penalty

Theft 29,839 81% 2461 8%

Other crimes 6,811 19% 688 10%

Total 36,650 3149 9%

Theft is vast majority of prosecutions, so decline in probability of death sentence for theft

Drives overall statisticsMasks increase in probability of sentence for other crimes

Relatively small change in case compositionIs it helpful to describe this as ecological fallacy? Contrast Simpson’s paradoxIs it problematic to say that legal system became more lenient overall?

Control for Case Strength• Maybe non-theft cases got stronger after 1718– So, given cases of equal strength, system was more lenient even

in non-theft cases• Maybe theft cases got weaker after 1718– So, given cases of equal strength, system got harsher in theft

cases• Potential controls– Value & type of stolen goods– Sex, age & status of offender– Relationship between offender & victim– # of witnesses– Prior convictions– Whether prosecutor or defendant had a lawyer– Literacy

Identify Actors and Mechanisms• Jury

– Pious perjury increased (only theft?)– Other ways for juries to affect sentence

• Judge– Sentencing discretion of judge

• More transportation for theft, but not for other crimes– More or fewer requests for pardons– Greater or lesser stringency in administration of benefit of clergy

• Legislators– Greater percentage of non-theft crimes eligible for death penalty– Changes in eligibility for transportation and/or benefit of clergy

• Neighbors– Less petitioning for pardons?

• Prosecutors– Less charging of capital offenses

Other Questions• Why focus on pre/post 1718?– Could test for other breakpoints– Could test for overall/continuous trend

• Death sentence versus execution?• Decision to prosecute– Coroner’s data for homicide

Conclusion• Important example of benefit of quantitative

analysis of legal history• Convincing• Additional analysis could make truly outstanding– Control for case quality– Explain which actors & mechanisms were responsible for

increase/decrease in leniency