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[Ward Farnsworth (guest-blogging), August 3, 2007 at 10:44am] Trackbacks
Cascades.

You have job interviews with two employers and are turned down in both of them. At the next one you are asked if you have had any prior interviews. You recount your unhappy recent history and the employer concludes that the two prior rejections probably meant something. This helps him decide to pass on you. The process continues and accelerates from there; the next interviewer finds you have three rejections and has even more cause for concern than the previous one.

This is an example of an information cascade. Notice that all the interviewers might be acting rationally. If you feel uncertain about something, it might make sense to defer to others who have already decided; maybe they knew more than you do. And if the next player likewise has no firm basis for decision it might be entirely reasonable for him to see the growing agreement, find it impressive, and go along. But whether reasonable or not, the result is that the belief gains a kind of empty momentum: there is growth in its acceptance but not in its likelihood of being true, which hasn't changed and may be small.

There are a number of implications for law. One involves the hazards of sequential decisionmaking. When witnesses are asked what they saw, they say different things alone than if they first hear how others describe the events; there are various ways to interpret this, one of which is that it's a kind of cascade. That is why the federal guidelines say that witnesses to crimes should be separated and shouldn't talk to each other.

A similar problem arises when jurors vote on a case. Should they vote simultaneously or sequentially? A simultaneous vote has the advantage of avoiding cascades: we don't want the third juror swayed by what the first two say, then the fourth juror swayed by what the first three say, and so on. So the choice of procedure might matter; oddly, though, we leave it up to each jury to decide what to do. The same general question arises again when judges vote. On the United States Supreme Court the Justices vote openly and one at a time, starting with the Chief Justice and then descending to the most junior member, who already knows how all the other Justices voted when his turn arrives -- suggesting a danger of cascades.

The risk of cascades repeats on a larger scale in elections. Think about cascades created by early primaries, for example, or by public opinion polls (which is why some countries ban them in the days or weeks before an election). Might a cascade also arise when courts in different jurisdictions are presented with the same question, one after the other? There are other interesting kinds of cascades, too, but this entry is getting long; so if you'd like to read about them (or more about the kind just described), they are the subject of one of the sample chapters available at the web site.

This post wraps up my guest-blogging for the week. I hope these discussions have piqued the interest of some of you in The Legal Analyst. The sample chapter just mentioned, and the others at the web site, should give you a clearer idea of whether the book is for you (they go into more detail than I've had space to do here); and there will soon be a fourth sample chapter available at Eugene's own site — the chapter on slippery slopes, which, as I mentioned before, I co-wrote with Eugene but is really just a short adaptation of his classic article on the subject. Thanks so much to Eugene and the other writers at his site for having me here, and to the many readers who have sent me suggestions or posted them to the comment threads.

Dave Griffith (mail):
At the next one you are asked if you have had any prior interviews.

Not that it invalidates the point, but why would an employer ask such a question? If asked, why would the candidate answer (beyond a somewhat obvious "I am currently pursuing other positions as well as this one").
8.3.2007 11:59am
Byrne Hobart (mail) (www):
Richard Dawkins wrote an excellent essay about why the jury system doesn't work in which he makes a similar point. I've seen it in recruiting, too — in general, when 99% of candidates need to be rejected for a position, one screening technique is to outsource rejection to everyone else.

Fortunately, personal networks mitigate this somewhat (your friends or friends of friends aren't going to be nearly as likely to turn you down for a position because you turned down a previous one).

The more interesting question would be the extent to which information cascades are responsible for success. In software and hedge funds, I'm pretty sure they explain a large fraction of the marketshare held by the top few participants.
8.3.2007 12:01pm
Constitutional Crisis (mail):
Dave Griffith wrote: "[W]hy would an employer ask such a question?"

Dave Griffith has obviously never interviewed for a federal clerkship...
8.3.2007 12:09pm
Dan Weber:
I sure hope that doesn't count as an excellent Richard Dawkins essay, because he tries to shoehorn jury decisions into binary yes/no answers, whereas juries have lots more flexibility than that. ("Yes on murder 2, no on murder 1.")
8.3.2007 12:21pm
DJR:

Might a cascade also arise when courts in different jurisdictions are presented with the same question, one after the other?



The Supreme Court has institutionalized cascade decisionmaking in two ways. First, it prefers to review only those questions that have produced a split in authority. Thus, if a question is initially decided one way, and other courts uniformly follow the first court's interpretation, it is unlikely ever to be reviewed in the Supreme Court. Second, the Court often waits until a question has "percolated" in the courts of appeals; i.e, until a sufficient number of courts have weighed in on the question. In theory, the more judges that look at the issue, the more likely that the decisions will reflect the strength of the various arguments; producing different results only if the competing arguments have comperable strength.

One could argue that in order to be important enough for the Supreme Court, the interpretation that is contrary to the one adopted by cascade should have at least enough support that one court is willing to go against the tide. That raises the question of how much weight courts should give to the decisions of other courts on the same issue. Theoretically, non-binding decisions of other courts are merely persuasive, and each court should perform its own analysis, but it's quite common to see a court of appeals note that a particular question has been uniformly decided by other courts of appeals, and seem to accord weight to the number of other courts that have already decided the issue.
8.3.2007 12:40pm
anonVCfan:
You have job interviews with two employers and are turned down in both of them. At the next one you are asked if you have had any prior interviews. You recount your unhappy recent history and the employer concludes that the two prior rejections probably meant something. This helps him decide to pass on you. The process continues and accelerates from there; the next interviewer finds you have three rejections and has even more cause for concern than the previous one.

This is also how some rules propagate among the federal courts of appeals when the courts get lazy.
8.3.2007 1:07pm
GD (mail):
Days on the market can have a similar effect in residential real estate.
8.3.2007 1:13pm
byomtov (mail):
But shouldn't the third interviewer take into account that the second rejection was influenced by the first, so it was not a completely independent event?
8.3.2007 2:04pm
CJColucci:
Ward's been here a week, now he's leaving, and neither he nor anyone else will answer my question about whether he's related to E. Allan?
8.3.2007 2:32pm
Ward Farnsworth (mail):
I was informed that an original comment in the post about military courts was erroneous, so I deleted it; thanks for the comments. As for the question about whether I'm related to Allan Farnsworth, no, I'm not. WF
8.3.2007 4:25pm
Randy R. (mail):
Cascades also works with dating, sadly.

You go out on a date, and your date asks you if you have ever been in a relationship. If you say no, they think at your age, something must be wrong with you for not having a relationship.

If you say yes, then he might ask, what went wrong? Whatever your answer, you are cornered, because of course every other relationship failed -- that's why you are on a date! So he wonders that something must be wrong with you if you failed at every other relationship.
8.3.2007 5:52pm
Connie:
Dating, hell, it also works with marriage. "Why aren't you married yet? There must be something wrong with you."
8.3.2007 10:29pm
TerrencePhilip:
Randy: maybe you could tell them "well actually I'm in a relationship with someone now"- proving both your ability to sustain a relationship, and your versatility. Start your own little cascade, player!
8.3.2007 10:52pm
OrinKerr:
Great having you, Ward. I enjoyed your posts and I look forward to reading the book.
8.4.2007 12:52am
Smokey:
The ultimate in cascade voting is in Congress, where a Representative can vote, then watch how others vote, then change his vote if it's expedient.
8.4.2007 10:37pm