Separate trials or bifurcation of a trial keeps a lawsuit intact, but allows the judge or jury to hear and determine one or more issues without trying all of the issues at the same time. This is often done to avoid unnecessarily prejudicing or inflaming the jury with evidence related to one issue that is not related to another issue. For example, courts sometimes order separate trials or bifurcation of a trial when a party is seeking punitive or exemplary damages, and the court does not want evidence of the person’s net worth or the entity’s valuation or revenue—which are relevant to punitive damages—to influence the jury’s decision on whether the person or entity is liable for the breach of contract, negligence, or other claim. In such a bifurcated trial, the jury does not hear evidence of the net worth, valuation, or revenue unless it first finds the defendant liable on the underlying claim.

In Oregon, the concept of separate trials or bifurcation is addressed under the Oregon Rules of Civil Procedure (ORCP). According to ORCP Rule 53, a court may order a separate trial of one or more separate issues, claims, crossclaims, counterclaims, or third-party claims when it would be in the interests of convenience or to avoid prejudice, or when separate trials will be conducive to expedition and economy. Bifurcation is often used in cases where there is a concern that certain evidence may unfairly prejudice the jury. For example, in cases seeking punitive damages, a court may bifurcate the trial to prevent the jury from hearing evidence about a defendant's financial status until after they have determined liability on the underlying claim. This is to ensure that the decision on liability is based solely on the evidence related to that issue and not influenced by the potential for a large punitive award. The decision to bifurcate a trial is at the discretion of the court and is made on a case-by-case basis.