How abolishing the death penalty led to more convictions

THOUGH no one has been executed in Britain for over 50 years, until 1998 someone convicted of high treason or “piracy with violence” could in theory be put to death. The law is now clearly against capital punishment, but Britons are not. Fully one-third would like the death penalty to be brought back; the leader of the populist UK Independence Party has suggested a referendum on the matter. Yet research presented at this week’s Royal Economic Society conference suggests that if you really want to be tough on criminals, killing off capital punishment makes sense.

Anna Bindler and Randi Hjalmarsson, both of the University of Gothenburg, examined over 200,000 cases from the Old Bailey criminal court in London from 1715 to 1900. During this period capital punishment was abolished for many offences, from counterfeiting money (in 1832) to robbery (in 1837). Making the necessary statistical controls, the authors looked at the change in the likelihood of conviction for offences that were no longer capital.

The paper suggests that when capital punishment was an option, juries were often reluctant to convict at all. They may have felt it was a little rum to send someone to the gallows for stealing a cow, so they downgraded the charge or acquitted the defendant. The authors find that juries were particularly reluctant to convict women.

Once death was off the table, however, jurors could convict with a clearer conscience. The paper finds that the abolition of capital punishment increased the chance of conviction for all crimes by around eight percentage points, with especially large effects for violent offences. The temporary halt of penal transportation during the American war of independence had a somewhat smaller effect on the likelihood to convict, suggesting that juries considered living in America to be a prospect slightly less awful than death.

Past research has found that would-be criminals are more put off by an increased likelihood of conviction than they are by more severe sentences. If so, then getting rid of the most brutal punishments could make criminal-justice systems work better. If the third of Britons who would like the death penalty reintroduced got their way, the country might inadvertently end up letting more criminals walk free.