The addition of women to juries in England in the early twentieth century had a significant impact on conviction rates, particularly for cases in which women were prominent as victims or defendants. That is the central conclusion of research by Professors Randi Hjalmarsson, Patrick Bayer and Shamena Anwar, which is forthcoming in the Economic Journal.

Their study of the effect on criminal court jury decisions of making women eligible to serve on English juries in 1921 finds that:

• Despite little effect on overall conviction rates, female representation substantially affected the likelihood of conviction for a subset of cases in which female jurors might have viewed the alleged behaviour or its impact on the victim from a different perspective than their male counterparts.

• Specifically, female representation on juries increased conviction rates in sex offence cases by 16 percentage points.

• Female representation on juries also led to the emergence of a conviction rate differential between violent crime cases in which the victims were male or female. Cases in which the victim was a woman were now 20% more likely to lead to convictions compared with cases in which a man was the victim.

• Convictions for female defendants charged with ''other'' offences, many of which were related to abortion, were greatly reduced.

Though historical in nature, these results raise concerns about the basic fairness and effectiveness of modern criminal justice systems that exclude (or severely limit the role of) women. Such concerns are not limited to societies that completely exclude women from serving as judges and jurors but extend to courts or institutions, such as the military, where the historical overrepresentation of men in positions of authority continues to limit the role of women in judicial decision-making.


It is notoriously difficult to disentangle the impact of the addition and expansion of female participation in civic, political and economic life from the views of those who elected or appointed them.

In the new study, the researchers take advantage of the introduction of women into the English jury pool – the group of people from whom the final jurors are selected – to shed light on this question. Termed the ''great experiment'' by newspapers of the time, women became eligible to serve on English juries with the passing of the Sex Disqualification (Removal) Act of 1919, which was implemented in 1921.

One advantage of this historical context is that it studies the impact of including female jurors on what had been all-male juries. This provides a sharper and more meaningful comparison for assessing the broad impact of female representation, rather than the effect of adding one more female to the mostly gender-balanced juries of today.

The researchers use an original data set of more than 3,000 criminal cases from archival handwritten court records of the First and Second Courts of the Old Bailey – the London criminal court – from 1918 to 1926, including most importantly the names of all individuals seated on the jury. More than half of seated juries in 1921 had at least one female juror and more than 80% of cases in the following years had female jurors. But women were less likely to be represented on sex offence cases.

To avoid biases due to such potential selection, the main empirical analysis is based on a comparison of verdicts from the full set of trials before and after the introduction of the reform. The estimated effect therefore encompasses many potential mechanisms. The most obvious is that eligibility leads directly to female representation on juries, thereby affecting deliberations and decisions.

But the reform may also indirectly affect verdicts even in cases in which women are not seated on the jury. This could occur, for example, if the judge makes comments to the entire jury pool about whether the nature of the case is ''sensitive'' for female ears or if pre-trial selection is focused on striking potential female jurors, which could affect the resulting distribution of seated male jurors.

''A Jury of Her Peers: The Impact of the First Female Jurors on Criminal Convictions'' by Shamena Anwar, Patrick Bayer, and Randi Hjalmarsson is forthcoming in The Economic Journal.