# weight of evidence

(redirected from Bayes factor)
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## Weight of Evidence

Measure of credible proof on one side of a dispute as compared with the credible proof on the other, particularly the Probative evidence considered by a judge or jury during a trial.

The trier of fact in a civil or criminal trial, whether a judge or a jury, must review the evidence presented, evaluate it, and determine if it meets the standard of proof. If it meets this standard, the trier of fact must return a verdict in favor of the plaintiff in a civil suit and must convict a defendant in a criminal trial. If the evidence does not meet the standard of proof, the trier of fact must find for the defendant in a civil or criminal case. These decisions are based on the concept of the "weight of evidence."

The weight of evidence is based on the believability or persuasiveness of evidence. The probative value (tending to convince a person of the truth of some proposition) of evidence does not necessarily turn on the number of witnesses called, but rather the persuasiveness of their testimony. For example, a witness may give uncorroborated but apparently honest and sincere testimony that commands belief, even though several witnesses of apparent respectability may contradict her. The question for the jury is not which side has more witnesses, but what testimony they believe.

Particular evidence has different weight in inducing belief with respect to the facts and circumstances to be proved. Evidence that is indefinite, vague, or improbable will be given less weight than evidence that is direct and unrefuted. For example, a criminal defendant's testimony that he had never been at the scene of a crime would be given little weight if his fingerprints were found at the crime scene and witnesses testify they saw him at the scene. Similarly, evidence given by a witness who testifies from personal observation is of greater weight than evidence offered by a witness who is testifying from general knowledge alone.

In a civil trial, the plaintiff's Burden of Proof is the preponderance of the evidence standard, which means that the plaintiff must convince the trier of fact that the evidence in support of his case outweighs the evidence offered by the defendant to oppose it. In contrast, criminal trials require that the weight of evidence proving a defendant's guilt must be Beyond a Reasonable Doubt.In a number of jurisdictions, judges are prohibited from instructing juries on the weight to be given to evidence. In other states, the judge is permitted to give a balanced and fair assessment of the weight she believes should be ascribed to the evidence. All jurisdictions prohibit the judge from instructing the jury on what weight is to be given to the testimony of any witness or class of witnesses. The judge may not state that any particular piece of admissible evidence is or is not entitled to receive weight or consideration from the jury. The judge is also forbidden either to aid a jury or to infringe upon its role in weighing the evidence or in deciding upon the facts. In addition, the judge, in giving her instructions to the jury, has no right to prescribe the order and manner in which the evidence should be examined and weighed by the jury, or to tell the jurors how they shall consider any evidence that has been received by the court.

## weight of evidence

n. the strength, value and believability of evidence presented on a factual issue by one side as compared to evidence introduced by the other side. (See: evidence, preponderance of the evidence)

## weight of evidence

noun adequate evidence, adeeuate proof legally presented at trial, burden of going forrard, legal responsibility, obligation of going forward, sufficient corroboration, sufficient evidence in a case, sufficient evidence to establish a case, sufficient proof, sufficient proof of facts, validation of proof of a case, verification of proof of a case
Associated concepts: cause of action or claim, evidence, evidential burden, failure to sustain, preponderance of the evidence, prima facie case, rebuttal
Foreign phrases: Onus probani.Burden of proof.

## weight of evidence

the degree of reliance that a court places on a piece of evidence.

WEIGHT OF EVIDENCE. This phrase is used to signify that the proof on one side, of a cause is greater than on the other.
2. When a verdict has been rendered against the weight of the evidence, the court may, on this ground, grant a new trial, but the court will exercise this power not merely with a cautious, but a strict and sure judgment, before they send the case to a second jury.
3. The general rule under such circumstances is, that the verdict once found shall stand: the setting aside is the exception, and ought to be an exception, of rare and almost singular occurrence. A new trial will be granted on this ground for either party; the evidence, however, is not to be weighed in golden scales. 2 Hodg. R. 125; S. C. 3 Bing. N. C. 109; Gilp. 356; 4 Yeates, 437; 3 Greenl. 276; 8 Pick. 122; 5 Wend. 595; 7 Wend. 380; 2 Vir. Cas. 235.

References in periodicals archive ?
The rule requires updating the "prior odds" (on the left-hand side) by multiplying by the Bayes factor (which also is the likelihood ratio L) to arrive at the "posterior odds" (on the right-hand side).
An expanded model that includes hospital volume displayed an out-of-sample log Bayes factor of 31.
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Variations of the model, termed model scenarios, were developed to investigate a number of hypotheses for the delay in recovery and these hypotheses were statistically compared using Bayesian model selection, which provides the probability of each model scenario (or hypothesis) given the data, through the use of the Bayes factor.
We calculated for each racial group a Bayes factor for the following four variables: dichotomous ([+ or -]) hair-assay outcome, dichotomous ([+ or -]) urinalysis outcome, yes/no response to query on cocaine use within the last 48 hours, yes/no response to query on cocaine use within the last 60 days.
The strength of evidence in favor of placing that sampling unit in the original stock against placement in the new stock is provided by the Bayes factor
The second term is called the Bayes factor and summarizes the sample evidence in favor of [M.
Discusses the Bayes factor, Deviance Information Criterion (DIC), and $L\nu$-measure for Bayesian model comparison.
A Bayes factor test conducted in TRACER yielded a strong estimate of superiority of the codon-based model over the GTR + [GAMMA]4 + I model ([log.

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