Freakonomics Blog: Juror Unanimity Isn't Necessarily a Great Thing

Here is a compelling take on the unanimity requirement of our legal system:

Juror Unanimity Isn’t Necessarily a Great Thing: A Guest Post
By Ethan Leib

Thanks for putting up with my quirky intellectual agenda of friendship and the law in the last two posts. For my final post, I thought I would highlight a more traditional area of my legal research: the jury.

There is something quirky at play here too: the U.S. is one of the few democracies around the world to have a unanimity rule for juror decision-making. The Times’s Adam Liptak has been doing a series on American Exceptionalism — “commonplace aspects of the American justice system that are virtually unique in the world” — but he has yet to focus on the puzzling persistence of unanimity as our jury decision rule.

Here are a few facts that make unanimity a non-obvious choice for juror decision-making.

1) We don’t require unanimity for any other important decision in our pluralistic polity. Our Supreme Court doesn’t decide by unanimity and neither do our legislators.

2) No other modern country (save Canada and a few jurisdictions in Australia) requires it.

3) We require unanimity to acquit as well as convict, so the idea that it contributes to protecting defendants is not fully accurate.
4) The symmetrical unanimity requirement contributes to inefficiency by giving us hung verdicts more than necessary.

5) Our juries have gotten more diverse as we’ve made it harder to get out of service and as we’ve grown more inclusive in our political system. With that diversity, majoritarianism seems more appropriate.

6) Empirical evidence tends to support the view that verdicts don’t change all that much when you change the decision rule. So the idea that unanimity contributes to certainty is probably overblown.

7) There is also empirical evidence suggesting that people assigned a unanimous decision rule will often agree to decide by supermajority (albeit unanimously) — meaning that in such cases, there is no difference between the two rules, except that some jurors agree to pretend that they agree with a verdict from which, in fact, they may strongly dissent.

8) We all know that many people are willing to falsify their preferences by changing their votes to agree with the majority; the incentives for doing so are especially high when one is a holdout juror being berated by other jurors because everyone wants to get home faster.

9) We don’t have such stringent unanimity rules in the context of the civil jury or courts martial, yet both those systems are respected and deemed legitimate by the public. Moreover, the few states that have experimented with relaxed jury-decision rules for the criminal jury — Oregon and Louisiana — do not suffer especial deficits in legitimacy.

10) Unanimity is often an illusion. Suppose a jury hangs, leading to a retrial. The second jury empanelled to try the defendant then convicts unanimously. Despite this second “unanimous” verdict, the truth is that, of a total of 24 jurors who heard the evidence, fewer than 24 were persuaded to convict. Indeed, it’s possible in theory that only thirteen — a bare majority — were persuaded, if in the first trial the holdout favored conviction, not acquittal.

These facts should be enough to get us to question our fealty to unanimity. At the very least, I think it is high time we stopped requiring unanimity for acquittals.