Source of article The Jury Room - Keene Trial Consulting.
The researchers report their data included “all felony and misdemeanor trials over a two-year period, and contain detailed information on defendant characteristics as well as case characteristics”. The information gathered also included demographic information on the jurors and so the researchers were able to calculate “the expected proportion of women on each jury” based on the variations each panel reflected in terms of gender. Some of you know that Florida seats both 6 person and 12 person juries, and the researchers took that into consideration. Here is what they found: Own-gender juries result in “significantly lower conviction rates on drug charges” although not on other charges [like “driving, property, or violent crime offenses”]. Even as small an amount as 10% above the expected gender-match on your jury results in an 18% reduction in conviction on drug charges. Own-gender juries also reflect differences in sentencing decisions with own-gender juries issuing lower sentences. In the case of sentencing, a 10% point change in expected gender composition of the jury will result in a 13% reduction in “the likelihood of being sentenced to at least some jail time”. These shorter sentence differences remain even when juries only issue a guilty or not guilty verdict and a judge determines the sentence! It is important to note that because they were attempting to identify the effect of own-gender juries, the researchers “excluded cases linked to charges in which fewer than 10% of the defendants were female. The researchers explain their reasoning for excluding certain types of cases this way: “Consequently, we only consider cases that involve a drug, driving, property, or violent crime. In addition, we limit violent crimes to domestic crimes assaults, and robberies. This is due to the low number of female defendants in other violent crime categories, such as sexual assault and murder, which gives us very little variation in defendant gender.” The researchers believe that randomly drawing a higher proportion of female jurors for a male defendant can result in unfair and “significant long-run costs”. They cite literature on variations in sentencing by gender of juror, as well as the literature on fairness in conviction and sentencing based on factors other than evidence presented at trial. In addition, they mention the literature on the presence of “one black juror” making a difference in conviction rates. Another intriguing aspect to this study is the researchers report that over 58% of their sample was charged with “possession of drugs or drug paraphernalia without intent to distribute”. The researchers suggest that when jurors who do not agree with sentencing rules for non-violent drug offenses (which, they point out, is a significant portion of Americans), they may engage in jury nullification and find the defendant not guilty. Specifically, they say it this way: “jurors fairly enforce the laws with which they mostly agree, but disproportionately favor own-group defendants when deciding whether to enforce laws with which they might not agree”. From a litigation advocacy perspective, if you are representing defendants accused of non-violent drug offenses, all other things being equal you should consider a same-gender jury. If, on the other hand, you are prosecuting, you will want other-gender jurors to achieve your goals. Hoekstra, M & Street, B. 2018. The effect of own-gender juries on conviction rates. National Bureau of Economic Research. http://www.nber.org/papers/w25013 
A new study by economists tells us it depends on whether you yourself are male or female. To examine the question of whether own-gender juries (i.e., jurors who are the same gender as you, the defendant) vary in conviction rates, the researchers looked at “detailed administrative data on the juror selection process and trial proceedings for two large counties
