How does jury selection work in a criminal trial?

Both Supreme Court and District Court trials are ordinarily heard before juries. A jury is a random selection of 12 members of the public, unknown to the accused, who have responsibility for determining if the accused is guilty or not guilty. Jurors are generally not legally trained people, although former lawyers can now sit on juries since amendments were made in 2011. For most jurors the trial they are deciding will be their first exposure to the criminal justice system.

The jury selection process is often quite confusing and fairly alien for accused persons. This article outlines some of the basic points to be aware of in a case involving a jury.

(1) When is a jury empanelled

A jury is empanelled, generally, when a criminal trial commences. In rare cases, a jury can be empanelled in a civil trial. But they usually only preside over criminal trials. That is, a hearing which determines an accused’s guilt for an indictable offence in the District or Supreme Court.

Juries are not empanelled for other hearings, such as trials of the issues, or sentencing hearings. There is provision for a jury to determine whether a court has jurisdiction to hear the charge(s) against an accused. An example of this situation is when an accused asserts they were 17 at the time of alleged offences, meaning the Children’s Court has jurisdiction, but they are charged in the District Court. However, this power does not appear to have been used very frequently if at all: in practice Judges decide jurisdiction in nearly all cases.

(2) What is involved in empanelling a jury

Empanelling a jury involves selecting the required number of jurors from a large “pool” of jurors. On the first day of your trial, the Judge will soon after the commencement time call the jury “pool” into the court. This can be upwards of a hundred people all crammed into the court room. These people will, before coming into court, have been shown a video by the Sheriff’s Office about serving on a jury. Some of them may have pre-written notes with excuses as to why they shouldn’t have to serve on the jury, such as work or personal knowledge of the case.

The required number of jurors varies depending on the length of the trial, and is chosen by the trial Judge. For short trials of about 3-4 days, a Judge may only request 12 jurors. This leaves no room to move if one of the jurors becomes unable to finish the trial because of sickness. For longer trials, a Judge may select 13 or 14 jurors, or sometimes more. This leaves a few spare jurors in case one or more jurors are unavailable by the end of the trial.

(3) How many jurors decide the case?

At the end of the trial, only 12 jurors decide the case. If more than 12 jurors were empanelled, the Judge will conduct a random ballot in which 11 jurors are chosen to go into the jury room to deliberate, along with the foreperson. As noted, the foreperson is guaranteed a spot. The remaining jurors are discharged from further service. This can be difficult as they may have sat through a lengthy trial only to be told they have to leave without getting to decide the matter.

(4) Can I challenge jurors?

As the jury is empanelled, you (or your lawyer) may challenge 3 jurors by way of a ‘peremptory challenge’. This is a right to challenge without giving any reasons. You won’t have much information about any jurors beyond their name, address, occupation and their appearance in court. The decision to challenge a juror is a complex one and you should seek expert advice about it.

Jurors themselves may seek to be excused for a variety of reasons. Sometimes their request may be refused and deciding whether to challenge that juror, who is forced to do jury duty against their will, can be difficult.

(5) Is there a head juror?

The jury must select a “foreperson” who is the ‘head juror’, but has no special voting rights or powers. This person speaks on behalf of the jury, and is guaranteed a spot in the jury room when it comes time to deliberate.

(6) Does the juries’ decision need to be unanimous?

Ordinarily a juries’ decision must be unanimous. In some cases, a Judge may direct that only 10 jurors may decide the case, if the jury cannot reach a decision unanimously after deliberating for at least three hours. A jury may also be hopelessly deadlocked, resulting in a hung jury. In this case there is no finding of guilt at all and usually a retrial is ordered.


Jury selection and empanelment can be quite a confusing process to experience, particularly if this is your first trial. It is important that you receive expert advice about your right to challenge jurors, and various other matters concerning juries. If you require expert advice about juries in a trial in Perth, Western Australia, don’t hesitate to contact us.

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