6 Key Differences Between a Grand Jury and a Trial Jury
At a Glance
Grand juries and trial juries serve very different roles in the criminal justice system, despite common misconceptions. This article explains how they differ in purpose, evidence rules, secrecy, participation rights, and decision-making—and why those differences matter if you are under criminal investigation or facing charges.
There are a lot of misconceptions and misunderstandings amongst average US citizens regarding the roles of the two main types of juries in the criminal justice system. Most people have a basic idea of how a trial jury—also known as a petit jury—normally works, with a group of the defendant’s peers being sworn to render an impartial verdict in the case after hearing the relevant evidence. However, the main confusion for most is with regard to grand juries.
The United States is the only common law country in the world that utilizes a grand jury system. Grand juries are used in criminal cases at the Federal level and in a majority of states, including Texas.
Many people mistakenly believe that grand juries serve essentially the same function as trial juries, and while these two are both comprised of average US citizens, they are in fact quite different.
Below we have detailed six of the biggest differences between grand juries and trial juries:
Role
A trial jury decides guilt beyond a reasonable doubt, while a grand jury only decides whether there is enough probable cause to indict and send a case to trial.
Trial juries hear the evidence and determine whether the defendant is in fact guilty, and they may also play a role in sentencing. Grand juries, by contrast, do not determine guilt or innocence. They simply decide whether the evidence against the suspect is significant enough to warrant a trial and potential conviction, and the prosecutor is not even required to adhere to the grand jury’s decision.
Attendees
Grand juries differ significantly from trials in that the defendant and his or her attorney cannot attend the grand jury proceeding. Aside from support staff, the proceeding will only be attended by the jurors, the prosecutor, a judge, and any potential trial witnesses whom the prosecutor chooses to present to the jury.
Evidence
Trial juries only hear very strict types of evidence that are allowable in court. Evidentiary requirements in criminal trials ensure that all evidence was legally obtained and fairly presented. Conversely, prosecutors may present any evidence they choose to a grand jury, including illegally obtained evidence.
Privacy
Trial jury cases are a matter of public record and open to the public in most cases. Grand jury proceedings are kept private, though the suspect and his or her attorney may eventually obtain a transcript of the grand jury hearing.
Time
Trial juries will generally meet nearly every day for a relatively short period of time. Grand juries will convene only a few times every month over a period of 6 months to over a year.
Unanimity
No. A trial jury of 12 must be unanimous to convict, but a grand jury can indict without unanimity, and at the federal level only 12 of the 16 to 23 grand jurors need to vote to indict.
That unanimity requirement is what makes a criminal conviction so demanding: every one of the 12 trial jurors must agree the defendant is guilty beyond a reasonable doubt, so a single holdout is enough to prevent a conviction. A grand jury faces a much lower bar, needing only a set number of votes rather than a unanimous one to return an indictment to the prosecutor.
If you’ve been caught up in a criminal case and your case is going to a grand jury or could potentially be going to trial, it is vital that you enlist the services of a skilled defense attorney to guide you throughout both processes. Contact the Whalen Law Office today to learn how we can help.
FAQ’s
What is the difference between a grand jury and a trial jury?
A trial jury decides whether a defendant is guilty beyond a reasonable doubt, while a grand jury only decides whether there is enough probable cause to indict and send a case to trial. Grand juries are also larger and do not have to be unanimous.
Does a grand jury decide guilt or innocence?
No. A grand jury does not determine guilt. It only decides whether the evidence is strong enough to justify a trial, where a separate trial jury decides guilt.
Does the prosecutor have to follow the grand jury’s decision?
Not necessarily. The grand jury advises the prosecutor, but the prosecutor is not required to adhere to its decision.