After being instructed by the judge as to the law applicable to the case the jurors consider by themselves, without the presence of the judge or any other person, the evidence submitted to them and the instructions given, and if they are able to do so they agree unanimously upon a verdict in favor of one party or the other. If they are unable to agree on a verdict then the case must be resubmitted in full before another jury, for according to the common law no verdict can be rendered one way or the other unless all the jurors concur therein. In some states there are constitutional provisions for a majority verdict or for a verdict of a specified number of jurors more than a majority and less than all, but any such provision constitutes a modification of the common-law jury trial.

The conclusion of the jury as to the facts reached under the direction of the court as to the law is a final and conclusive determination of the case which the judge must recognize and embody in the final judgment to be rendered by the court as the result of the trial. If it is manifest that the jury has not followed the direction of the judge in applying the law, the verdict may be set aside by the judge and a new trial granted. If the judge is satisfied that in some essential respect there is no competent evidence to support the verdict of the jury, he may set it aside as not supported by the evidence. If the judge is satisfied that the jurors have rendered their verdict as the result of passion or prejudice and not through a full and fair consideration of the evidence submitted, he may set it aside on that ground. If the jurors have been guilty of some misconduct such as conversing with persons outside of court with reference to the merits of the case while it is being tried, or have allowed other persons to be present during their deliberations, or have heard statements by fellow-jurors as to facts not shown by the evidence and calculated to influence them in reaching a conclusion, or have determined the result otherwise than by a consideration of the evidence, as by casting lots to determine what their verdict shall be, then the judge will set aside their verdict for such misconduct. The result of setting aside the verdict is in all cases that a new trial is ordered. No irregularity on the part of the jury in reaching a verdict will justify the judge in rendering a decision for one party or the other. The judge may also set aside a verdict and grant a new trial if he is convinced that he himself has committed an error in material rulings on the admission of evidence or in instructing the jury as to the law. In criminal prosecutions the rule that the accused shall not be twice put in jeopardy for the same crime makes a verdict of "not guilty" conclusive regardless of any error of law or misconduct of the jury (see above, § 232), but if the verdict is against the accused then the same judicial discretion may be exercised by the judge as in a civil case in setting aside the verdict and granting a new trial.