What Chance Of Innocence Can Be Tolerated For Conviction?

[Chimp]

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Maybe. I think it's a judgement call. I'm disposed toward the current unanimous system for criminal cases. But you have a point.


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Unanimity is not always required in the US. Many states allow majority or super-majority verdicts in civil trials. A much smaller number allow them in criminal trials. At least, this was the situation when I was in law school about 10 years ago.

As for the original question, I remember the prof. discussing this issue in my crim law class. Most students thought the acceptable probability was between 75-90%. I can't remember what I thought at the time, but I am probably closer to the high end of that range now. The consensus was that the criminal system was intentionally set up to be a PTB-style squishy definition rather than a defined probability. This contrasts with the civil verdict system, which everyone agrees requires nothing more than >.50.

I don't know if someone is actually suggesting that we ask each juror to assign his own estimated probability to his individual verdict, but I can assure you that most American jurors would not be able to grasp this concept. The real-world application of such a system would be laughably unworkable (e.g., jurors voting to convict while at the same time assigning their probability of guilt at 10%)

[TomCowley]

David: It's about a coinflip for the average COLLEGE FRESHMAN to be able to solve 10.9=5.3/X in under 30 seconds with a calculator. It's way worse than a coinflip to find somebody who can figure the odds of rolling a 6 in craps. The average person is so utterly incompetent with probability that they can't "accurately" judge any number besides 0, 50, and 100.

That being said, your argument in this case is obviously correct. The evidence obviously can't increase the likelihood of innocence, and the only way it can fail to decrease it are in the trivial cases where the evidence is meaningless (say the whodunit is 80% defendant, 20% defendant's identical twin, and both have the same rare shoe size).

[samsonite2100]

I'd say around 10%

[Metric]

Haven't read most of the thread but I do agree with David's POV that it would be best to encode "reasonable doubt" as a specific probability estimate of guilt.

In fact, I bet that leaving it vague is where a lot of discrimination comes into play. Based on the evidence, someone might estimate a 90% chance of guilt, and be willing to say this counts as "reasonable doubt" for a defendant they like and respect, but might not count as "reasonable doubt" if it applies to your local gang member scum.

No doubt this kind of discrimination will exist anyway, but I think working the evidence directly into a probability estimate probably encourages more objectivity than working the evidence into whatever strikes you as "reasonable" after you get a good look at the defendant.

[PairTheBoard]

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You claim this is only "moderately precise" and should be replaced by a Number. I definitely do not agree with you on that point.

PairTheBoard

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Where does David advocate changing the system other than for assigning a number probability for this hypothetical question?

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I'm not sure what you're talking about. The majority jury system question was a side issue raised by chezlaw, not David. David insists we translate the court's definintion of reasonable doubt into a Number representing a psuedo-probability for chance of innoncence. I object to this.


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I don't see anything in there that requires me to put the question in terms of "chance" or some kind of psuedo-probability model.

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The hypothetical question does. How does "reasonable doubt" not equate to say "reasonable 'chance' of innocence"?

Why do you avoid answering the hypothetical question?

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The question I'm talking about is, "What consitutes Reasonable Doubt"? The court has given us a definition of what constitutes reasonable doubt that does not involve any psuedo-probability or "chance" terms. They are Human terms. You ask how is it they don't "equate" to "chance of innocence"? The burden is on you to show how they do. Sklansky can't do that because it is not a mathematical assertion that they do "equate". It is a philisophical assumption. I suggest you read jason1990's posts on the "Shoe Size" thread if you want to understand this better. You can also read the Wikipedia entry for Baysian Probability.

You have not clarified anything by converting reasonable doubt to terms of probability. The kind of probability that would be refering to is not mathematical but philosophical, and if you look at the philosophical definition of it it refers you right back to what you think reasonable doubt means. The danger in doing this is that it opens the door to the proclamation of a mathematical probability model which we have no way of knowing actually fits reality. From this model Sklansky will try to force conclusions on us that contradict our best judgement for how reality is really working and if we disagree he will claim we just don't accept the math. Sklansky is not really a math expert though. Real math experts can point out the flaw in this approach.

The flaw comes in setting up the probability model. It's doubtful whether that is even feasible. It's nearly certain that Sklansky is not going to give us one that fits reality.

Without the probability model the "Number" he asks us to provide is just a subjective philosophical concept whose meaning is basically what we already have without it.

PairTheBoard

[chezlaw]

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The majority jury system question was a side issue raised by chezlaw, not David. David insists we translate the court's definintion of reasonable doubt into a Number representing a psuedo-probability for chance of innoncence. I object to this.

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The issue was raised by DS. He was very concerned that allowing freedom on reasonable doubt resulted in one loony causing a big problem. I pointed out that it doesn't.

chez

[Shakes]

I had a criminal law/procedure professor in law school (just a few years ago) who described the criminal standard of "beyond a reasonable doubt" like this:

"By a preponderance of the evidence" (the civil standard) means more than 50% certain.

"By clear and convincing evidence" (less often the civil standard) means something like 75% or greater certainty.

"Beyond a reasonable doubt" means at least 90% certain of guilt in order to convict.

This came from a criminal professor who seemed very much pro-defendant at times. I see no reason to divert from this assessment. However, I do think that juries often use a significantly lower standard of proof in criminal cases.

[David Sklansky]

I gave a precise definition of the pseudo probability as you call it. The juror is asked to imagine that there are 100 trials with the exact same evidence. How many of those defendents IN HIS OWN PERSONAL OPINION will be innocent. As it is, the juror is expected to give the answer "not many" before he convicts. So all I am saying is that it would be nice for jurors to be told what number should be considered not many.

[PairTheBoard]

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I gave a precise definition of the pseudo probability as you call it. The juror is asked to imagine that there are 100 trials with the exact same evidence. How many of those defendents IN HIS OWN PERSONAL OPINION will be innocent. As it is, the juror is expected to give the answer "not many" before he convicts. So all I am saying is that it would be nice for jurors to be told what number should be considered not many.

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I cannot imagine how there could possibly be 100 different trials with the exact same evidence. That scenario is a figment of your imagination. When I imagine 100 copies of the 1 situation that is in front of me, all I can see are either 100 guilty defendents or 100 innocent ones. I just don't know which. That is a philosophical difference in how we look at it. I am not bound by your philosophical view nor by the imaginary figment you have conjured.

PairTheBoard

[David Sklansky]

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I gave a precise definition of the pseudo probability as you call it. The juror is asked to imagine that there are 100 trials with the exact same evidence. How many of those defendents IN HIS OWN PERSONAL OPINION will be innocent. As it is, the juror is expected to give the answer "not many" before he convicts. So all I am saying is that it would be nice for jurors to be told what number should be considered not many.

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I cannot imagine how there could possibly be 100 different trials with the exact same evidence. That scenario is a figment of your imagination. When I imagine 100 copies of the 1 situation that is in front of me, all I can see are either 100 guilty defendents or 100 innocent ones. I just don't know which. That is a philosophical difference in how we look at it. I am not bound by your philosophical view nor by the imaginary figment you have conjured.

PairTheBoard

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You are simply wrong. The thought experiment while contrived is not unimaginable. And it has nothing to do with philosophy. To show this imagine that there is a horse race picking contest based totally on the information in the daily racing form. I'll say the races were already run to avoid a nitpick about past events vs future events.

There are one hundred DIFFERENT races with totally different horses. Eight horses in each race. But amazingly the past performances for horses one throug eight are EXACTLY the same as far as what is in the racing form. In other words all number ones look alike. All number twos look alike. Etc etc. But they are NOT IDENTICAL Horses. And there are differences among them and among the conditions of the races. Some relevant. Such as height and weight. Or what the track bias was that day. But that information isn't available to you. Just like all evidence is not available at the trial.

Anyway you are now asked to pick the winner of each race. Say number three looks much the best. So you pick him. But that means you would pick number three in ALL races. Now your contention if translated to this example would be that number three will either win all races or lose all races. But this would obviously not be the case even if they were running on a straightaway with no racing luck involved.

If you change all the races to two horses races between Innocent and Guilty, I would hope that you would now understand that my thought experiment does not presuppose some debatable "philosophy".