Probability In Determining "Reasonable Doubt"

When a juror in a criminal trial is asked to determine whether or not somebody is guilty "beyond a reasonable doubt," how certain does "beyond a reasonable doubt" amount to mathematically?


What I mean is; if "beyond Any doubt" is equal to being 100% certain, then is "beyond a reasonable doubt" somewhere around 51%? 80%? What?

collectively by 12 persons it should mean certain.

but in the real world nothing is, and even death and taxes are getting to be in doubt.

a better term would be absolutely sure.

hdpm can set us straight.

The law-school phrasing is somewhere in the high-90's. One problem with this, however, is that the test is applied to each element on which the state bears the burden of proof. Therefore, if there are, say, 7 things the state must prove in order to get a conviction, and proves each with 90% certainty, then the overall probability that someone is guilty can be less than 50%.

So in the example you provided, is it supposed to net out at the higher or lower figure, legally speaking?

that is not the way it works in practice however. nor do juries even consider "reasonable doubt." most times they basically just say that they felt he did it or not. or, worse yet they have an agenda which has no relation to the truth.


your mathematical percentages also dont make any sense in a way. the real question is whether it is likely that someone who is found by a jury to be 90% likely to have committed these seven acts is not the person who actually did them. there is a lot of publicity about the cases of innocents that are found guilty but my experience is that virtually everyone who is brought to trial is guilty. they do not merely get to trial on the whim of the prosecutor but based on how likely it is that they can prove each element of a crime. in reality it is more like a 99% certainty that the person on trial is guilty of the crime.


Pat

reasonable doubt = 95%

In the example it nets out at the lower figure, but is supposed to net out at the higher one.


Usually the judge tells the jury that they should find the defendant guilty beyond a reasonable doubt by means of holding the state to the proof of each element of the crime beyond a reasonable doubt. In other words: find him guilty by (say) 95% probability by finding each element true by a 95% probability. There generally isn't a discussion about how these don't necessarily mean the same thing.

This isn't what the research on jury verdicts suggests. Jurors generally do a better job of getting the facts straight than judges because they can deliberate over different perceptions and 6 heads are, as they say, better than one. They also tend to come from more diverse backgrounds, are less politically ambitious and far fewer are former prosecutors.


I agree that this scenario could rarely happen in a criminal case, but consider a complex civil claim where the jury has to find a dozen or so elements to be true by the standard of mere probability. In sharply disputed close cases where liability is found, it probably shouldn't be.

civil liabilty much easier to win...

Is beyond a reasonable doubt spelled out to the juries explicity? That is, in a mathematical formula or structure - or just in words that may be interperted differently by various people?


Is beyond a reasonable doubt- cummulative?


As a simple example, say a murder case, and the State has three elements: they place the suspect at the scene of the crime; they prove he/she owned or had access to and was physically in contact with the murder weapon during the time of the crime; and that there was a motive for the crime, say economic gain.


Can the State be weak on one point but strong on others so that overall there is no "reasonable doubt". In the above example say the state was "ironclad" in elements one and two but somewhat weak on the motive. Does this in a sense "ruin" the state's case.


From what some are saying, it appears that the state must prove every single element beyond a reasonable doubt. If just one link is weak then the whole chain crumbles. Are all links given equal weight? What if one of the links is not that important to the case as a whole?

I've always heard that if you, as a juror, find one piece of evidence unconvincing, you can just toss it out and and make a judgement based on the remaining evidence.


For example, let's say you have:


a.)a surveillance video of the defendant shooting the deceased.


b.)a gun that is liscensed to the defendant.


c.)a ballistics report showing that the defendant's gun was the gun used in the shooting.


d.) figerprints on the gun identified as belonging to the defendant.


Okay, now the next piece of evidence is testimony from one of five witnesses, and let's say you don't find his testimony to be paticularly credible. Well from what I've always heard, you just toss out that piece of evidence(his testimony) and base your decision on the remaining evidence.

The probability that Chris Alger defies the laws of Colorado are 100%. I wouldn't trust anything that an attorney says when he has no respect for the laws of the community in which he lives.


He truly should be banned. He is clearly a racist, clearly illegally employed by online gambling establishements, and is not banned because the company he works for advetizes here.


Malmuth, and David Sklansky have clearly shown that they have no social conscioussnes whatsoever.

you are right i think in civil cases. but the standard is not reasonable doubt. in new york it is a "preponderance of the evidence" so eesentially it is a 51%-49% type of analysis. This is part of the reason i am pessimistic on the fast food lawsuits.


Pat

they must prove every element. if there is reasonable doubt about one element then there is no conviction. so the state can have an ironclad case on two issues but not the rest. this is why you sometimes see murder cases result in not guilty verdicts for murder, but guilty on manslaughter. the difference is that the state cant prove malice aforethought of whatever the particular state's standard is for murder. they can prove that A killed B but not that A did so with the required intent.


Pat

There is no mathematical formula or percentage. There really is no good formulation of it either. The reasonable doubt instruction in my state is meaningless. It essentially says reasonable doubt is the kind of doubt based on reason and common sense, not speculation because all things relating to human affairs are susceptible of possible or imaginary doubt. The incomprehensible part of the instruction speaks of proof to a "moral certainty" which snuck in the instruction long ago either by mistake based on a judges comment or that people used that term and understood it in 1837 or whenever- there is some dispute about it. A lot of states have language that says reasonable doubt is the kind of doubt that leaves jurors hesitant to act in the most important affairs of their lives. Other states have gotten the language wrong and say if jurors "hesitate" to act there is a problem. (I think Colorado's instruction is like this.) I don't like these instructions because I think they can misstate the law making the burden either lower or higher than it should be. And the decision the jurors are about to make is one of the most important affairs of their lives if the case is serious. Some of the federal courts have pretty good instructions, but I don't remember them. I researched them once in the hope of persuading a state court judge to use a comprehensible instruction. But the supreme court in my state has strongly cautioned judges from using an instruction different from the incomprehensible one, so I have resolved to live with the bad one.


The best formulation of the standard is one a crusty old judge used. After reading the stock instruction, he would look over his glasses at the jury and say, "That means you have to be damn sure he's guilty." That is as mathematically precise as the language on reasonable doubt will ever come I think.

The reasonable doubt standard applies only to the elements of the crime, not individual pieces of evidence. For instance, the standard for admission of any piece of evidence under the Rules of Evidence is much lower. For instance, to get a weapon admitted into evidence, the state only has to show by a preponderance it is the weapon found at the scene or in the defendant's hand or whatever; just enough to show that the evidence is relevant and tied to the case. How the jurors weigh that piece of evidence is up to them. So let's say that an element of the crime is that a weapon was used. If the state shows that a knife was found at the scene of the attack and bring it into court, that piece of evidence is coming in. But that does not mean the element of using the knife has been proven. There is no requirement that the jurors agree or make up their minds on all the pieces of evidence, just on whether the evidence proves the elements of the crime. The judge decides what evidence comes in, jurors decide what it means.

Pat Dicaprio said the same thing essentially, but I thought an example might be useful. The jury gets told what reasonable doubt means, but nobody understands it. (see my post below to the original question.) Then they get an "elements instruction" that spells out what the state has to prove. It would look something like this:


In order for you to find the defendant guilty of murder, you must find that the state has proven the following elements beyond a reasonable doubt:


1. On or about December 1, 2001;

2. in the state of Montana;

3. The defendant, Joe Guilty;

4. Did, with malice aforethought;

5. kill and murder Joe Dead;

6. a human being;

7. with no legal justification or excuse.


This is only an example and is not necessarily legally adequate, etc... The jury has to find each of these things beyond a reasonable doubt. The state has to show the crime occurred in the state where it is being prosecuted.(Federal cases are different.) That is because each state only has jurisdiction for crimes within its borders. A mundane fact in most cases, but not when a body is moved and one state has the death penalty and a neighboring one doesn't. The state has to prove the defendant did the act charged and not somebody else, i.e. the armed robber in a mask who says it wasn't him, but another guy. They have to show that the defendant had the requisite mental state, in this example, killed with "malice aforethought". There would be a bunch of other instructions defining what that term means. The state to prove a murder usually also has to show that the victim was a human being. Maybe this law will change when someone caps Mork or ET or something. Obviously, it is a lot easier to prove the element of the victim being a human and alive before being killed than it is to prove the mental state of the defendant. But it is only these elements that must be proven, not other things. For example, the state is entitled to present evidence of motive, but what the defendant's motive was is not an element usually. (sometimes aggravating factors or hate crime things do require proof of motive, but this is not the usual situation.)

,.,.,.

Thank you for the explanation HDPM. It is at least somewhat clear what it all means. Ditto also for your post below.


-Zeno