Efficient excusing

I have twice been excused from jury service when the jury duty conflicted with exam preparation and supervision; fortunately, I haven't been called during times of the year when I'm not teaching.

The Herald wonders whether lawyers Googling jurors helps them craft more convincing arguments for that particular jury. But that's gotta be a massively second order effect relative to Googling's effect on jury selection. Any Crown attorney Googling me would find I support jury nullification* in drug cases or for any other victimless crime and would knock me out before I made it onto the jury. Any Defence attorney would find I support that those actually imposing harm be made to make the victim whole, and likely would knock me off the jury on that basis. So it's efficient that I not be in the jury pool at all: the odds that I'd fail to be knocked out by one side or the other are exceedingly low, my time is worth something, and the process of being excused from a series of trials because of challenges is lengthy.

But think about the pool of people who would not be challenged by either side in a world where a rather substantial portion of potential jurors blog, tweet, or put stuff on Facebook.

It actually makes for a fun option value / optimal stopping rule problem. Here's the game, as described on the Justice website:

 The sequence of events at the beginning of the trial is as follows: the persons who have been called for jury service ("the jury panel") are brought into the courtroom where they sit at the back.⁷ Once court staff, counsel, the accused and the Judge have entered the court room the counts in the indictment are put to the accused, who pleads to them. Then the jury is chosen by ballot from the jury panel. The Registrar calls out each name as it is chosen, and that person walks from the back of the court to the jury box. If the person sits down before being challenged, they become a member of the jury unless they are discharged.

The page above is out of date; the number of peremptory challenges has dropped from six to four; I trust that the rest of it hasn't fallen out of date. But here's the basic game. Each side can challenge potential jurors as they are drawn from the pool of 30-40 who sit at the back of the room. If a juror is actually not qualified to serve, he can be challenged. Each side can challenge four without cause - peremptory challenge. I am not sure if there is a limit to the number of challenges for cause that can be made, but the judge has to be happy with the cause. Presumably my "anybody caught smoking a joint, and who admits having smoked a joint, is nevertheless innocent regardless of the law" views, as well as my three-day-a-week-anarchist status, would have me challenged for cause.

Suppose you're a lawyer who has to decide when to use your challenges to best serve your client's interests. So, when you got the list of potential jurors a couple days before the trial, you Googled them and gave each a score on the [-1, 1] interval indicating how hostile they were likely to be to your client's interests; you might also have noted your uncertainty about each score.** If you're the defence attorney on a drug trial where it's only a possession or trafficking charge, you give Crampton a +1 with zero variance (but you also know the Crown will veto); if you only find that somebody has 420 on his Facebook page, maybe you give him a +0.5 with a wider confidence interval. When you walk into the room, you check to see who is in the jury panel for the day; you then array the jurors from most to least hostile along with the scores you'd already given them. As each juror is called, the composition of the panel and of the jury changes, and so too then should the value of a held peremptory challenge: you have to weigh the hostility of the juror you reject with certainty against the odds that a more hostile juror might come up when you've run out of challenges.

I'd be pretty surprised if this hasn't been modeled before. But if it hasn't been, it would be a fun honours project. It would also be fun to see whether you can make an efficiency case for the reduction in peremptory challenges from 6 to 4 as lawyer certainty about juror views tightens up when they can Google potential jurors. File it under "Potential Honours Projects", if it hasn't already been done.

* UPDATE: It occurs to me that many Kiwis will have no clue about jury nullification. In short, it's the idea that a juryman must evaluate both the facts and the law. If the law is unjust, the jury must acquit no matter what the judge says. Juries are only a bulwark against tyranny if they are willing to overturn unjust laws by refusing to convict peaceful people for doing peaceful things. That's the point of juries. Expert judges will beat juries in assessing the facts, and especially so in complicated cases. Read Lewis Carroll on the competence of juries. But juries can assess whether it would violate the community's norms if the law were upheld. Consequently, there are no circumstances under which I could render a guilty verdict in a case involving victimless crimes. And so I know that I would never be chosen to be part of a jury. I do not expect or purport that most people here or anywhere else agree with me about the desirability of nullification; if they did, there wouldn't be prohibitions in various places on telling juries about nullification.

** Doubt lawyers do this explicitly; would expect decent ones do it implicitly such that a Friedman "as if" move works. Note that most of my knowledge of actual jury selection comes from an old Al Pacino movie. Keanu Reeves couldn't really Google the jurors in 1997. But things have changed....