There are usually two things that can happen when there is a hung jury: the judge can ask the jury to reconsider and hope that more time might lead some jurors to change their minds, or the judge can declare a mistrial. A mistrial is usually the more serious and time-consuming outcome. It usually requires starting the entire trial over again with a new set of jurors. The rules tend to be a little bit different depending on the jurisdiction and the type of court, but hung juries almost always mean trouble for the lawyers, the parties, and the courts involved. Participants typically do all they can to avoid this outcome.
Many court systems around the world use juries to help reach a conclusion in certain cases. The specifics of the selection and ordering process are different from place to place, but in most instances a jury will consist of anywhere from 9 to 13 people selected from the community. Some court rules require complete unanimity, whereas others want only a majority vote on decisions of guilt, innocence, and punishment specifics. When these requirements can’t be met, the jury is usually said to be “hung.” In practical terms this means that the jury wasn’t able to make a decision, which usually means that the court isn’t able to enter a verdict or final decision.
The main role for a jury in any setting is to render the verdict, often expressed in terms of guilt, innocence, or liability. Deciding on the punishment or consequences is sometimes but not always also included. It’s typical for the jury to listen to the entire proceedings, hear all the testimony, and see all the evidence that is submitted while the case is being tried.
After the closing arguments, the jury begins a process called deliberation. While they are in deliberation, jurors are alone with one another in a private room discussing the disposition of the case. They have access to transcripts of the testimony and any evidence is usually also available for their review.
What Disagreement Looks Like
Under ideal circumstances, jurors should be able to take as much time as they need for deliberation, within the bounds of practicality of course. The key objective is for them to be united on a verdict. This isn’t always possible, though. In some countries, the jury needs to be in unanimous agreement to render a verdict, particularly in criminal cases. This is usually the case in the United States. Elsewhere, though, particularly in Canada and the United Kingdom, a majority agreement is enough. A situation where 10 out of 12 jurors agree on a particular charge may be sufficient in some places, for instance, whereas in others even a slight imbalance like this would be considered a hung jury.
There are a number of reasons why juries become hung, and the problem often involves differences of opinion, different interpretation of evidence, and different impressions of the parties and their lawyers. In some cases it may also be the result of personality conflicts or wildly divergent backgrounds and approaches to justice.
A hung jury is usually considered bad for everyone involved, and as a result there are a couple of things lawyers and judges can do to prevent them. One of the most important parts of this process is the actual jury selection, which usually happens well before the case is tried. Lawyers for both parties usually have the opportunity to interview and select the members of their jury from a pool of qualified people. Lawyers for both sides tend to work together in the selection process to choose a jury that will be balanced and objective.
If it looks like there may be an impasse when it comes time for a decision, the judge might take some time to discuss the situation with the jurors and ask those who are in the minority to reconsider their position. In the U.S. this is frequently called an "Allen charge." In the course of this charge the judge typically reminds the jury of the importance of reaching a conclusion in the trial and how much time and effort has already been spent. Whether or not a judge has the ability to influence the jury this way often depends on the local rules as well as the sort of matter being tried.
When there really is no solution, the court often has no option but to declare a “mistrial” and start over. Mistrials are fairly serious and usually mean that some procedural or technical error made the case impossible to resolve, and the parties must start over again — often at great expense of both time and resources.