Justice Sonia Sotomayor's elevation to the Supreme Court brought to the surface a long-simmering controversy about the relationship between gender and judging. Are female nominees for judicial positions chosen based on affirmative action? If so, are women on the bench worse judges than men—or do they come with advantages that men lack? This controversy has legs. If Justice Ginsburg is forced to retire this term because of illness, reducing the number of female justices from two to one, there will be a great deal of pressure on President Obama to nominate another female jurist. Or if Justice John Paul Stevens retires, why not three women on the high court?
Many conservatives believe that gender should not factor into the choice of judges and justices. For them, Sotomayor was an affirmative action candidate. Because many fewer women than men went to law school in the 1970s and 1980s, and more women drop out of legal practice to care for their families than men do, the pool of judicial candidates today is dominated by men. It stands to reason that if male judicial candidates are passed over in favor of women, less qualified people will be selected.
Yet there is an alternative view: that women may actually be better judges. Sotomayor herself obliquely expressed this view long before her nomination, saying, as we heard repeated often last summer, "I would hope that a wise Latina woman with the richness of her experiences would more often than not reach a better conclusion than a white male who hasn't lived that life." Most women, unlike most men, know what it is like to be discriminated against and oppressed and, if they want to succeed, must "learn to see both sides in ways that men do not," as Slate's Dahlia Lithwick put it. Men face no similar pressures and so live in a happy bubble of illusion. Because the job of the judge involves seeing other people's perspectives, female judges have a real, albeit hard-won, advantage.
The claim that women are worse—or better—than men at judging should be susceptible to empirical investigation. There is no obvious way, however, to measure judicial quality; lawyers dispute endlessly whether cases are rightly or wrongly decided—and, ultimately, a good judge is just a judge who decides cases correctly. Still, we have come up with some indirect measures of judicial quality. These include productivity (how many opinions judges write), influence (how frequently other judges rely on their opinions), and independence (how often judges dissent from opinions written by judges who belong to the same political party). We looked at the performance of hundreds of judges over a number of years and working in different types of courts—state supreme courts, federal trial courts, and federal appellate courts. (Our paper is here.)
We found that the conservatives are right about one thing. On average, female judges are less qualified, based on traditional metrics, than male judges. They have attended lower-ranked colleges and lower-ranked law schools, they are less likely to have had judicial clerkships (a prestigious job often taken by top law school graduates), and they have less experience in private practice before becoming judges. This suggests that the pool of stellar female candidates for the judiciary is smaller than the pool of stellar male candidates, which provides ammunition for the conservative argument that President Obama's choice of Sotomayor, or another female justice, involves affirmative action in favor of women. If female judges are chosen on the basis of sex rather than ability, they must be less talented than male judges, the theory goes. If they were just as good, it would not be necessary to put a thumb on the scale in their favor when evaluating judicial candidates.
Yet when it comes to performance rather than qualifications, we find no statistically significant differences between the decision-making ability of male and female judges in any of our data sets. Female judges are cited just as often as male judges; they write as many opinions; and they are just as likely to dissent, and to dissent from opinions written by judges who belong to their party. Indeed, female judges with the same level of experience as male judges are more likely to dissent from opinions written by fellow Democratic or Republican appointees, suggesting perhaps that women on the bench are less influenced by political considerations or are just tougher nuts than their brethren.