In the United Kingdom voir dire is not used for jury selection. It is used to decide what evidence can and cannot be presented during the trial. This can include confessions made to the police. In Australia and Canada, voir dire is used as a sub-trial within a trial to examine evidence. It is usually done with the jury absent from the courtroom. In Canada, voir dire can also be used to challenge a particular juror for cause (for a specific reason). But cases of challenging a juror under voir dire are rare in Canada.