Scientific jury selection

Scientific jury selection, often abbreviated SJS, is the use of social science techniques and expertise to choose favorable juries during a criminal or civil trial. Scientific jury selection is used during the jury selection phase of the trial — when lawyers have the opportunity to question jurors and they and the judge choose which people will be on the jury. It almost always entails an expert's assistance in the attorney's use of peremptory challenges — the right to reject a certain number of potential jurors without stating a reason — during jury selection. The practice is currently confined to the American legal system.

SJS has roots in criminal trials during the Vietnam War era, but in modern times is usually employed in high-stakes civil litigation (where only money is usually at issue, in contrast to criminal trials, where the defendant can go to prison). SJS practitioners determine what background characteristics and attitudes predict favorable results, and then coordinate with attorneys in choosing the jury. Studies are mixed as to the effectiveness of the practice, though it is clear that the evidence presented at trial is the most important determiner of verdicts (the trial result) and that SJS is more likely to have an impact where that evidence is ambiguous. SJS's potential to unfairly skew the jury has led to some reform proposals, but none have yet been implemented. The limited fictional portrayals of SJS have been negative towards the practice.

During jury selection in the United States, attorneys have two options for excluding potential jurors. The first option is a challenge for cause, in which attorneys must state the reason for a challenge (such as clear bias or a conflict of interest), the opposing party is allowed to respond, and the judge decides whether to exclude the juror. The second option is a peremptory challenge, where an attorney can exclude a juror without stating any reason. While challenges for cause are unlimited, attorneys have a limited number of peremptory challenges, sometimes as few as four, although 10 is more common in non-capital felony cases.

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