Legal Definitions - offer of proof

An "offer of proof" is a formal statement made by a lawyer during a trial when the judge has decided to exclude certain evidence. When one lawyer attempts to present evidence—which could be a document, a physical item, or a witness's testimony—and the opposing lawyer objects, the judge might agree with the objection and prevent that evidence from being shown to the jury.

At this point, the lawyer whose evidence was excluded can make an "offer of proof." This typically happens outside the jury's hearing. In this statement, the lawyer explains to the judge:

• What the excluded evidence is (e.g., what the witness would have said, or what the document contains).
• Why they believe this evidence is important and relevant to their case.
• Why, according to the rules of evidence, it should have been admitted.

The "offer of proof" serves two main purposes:

1. It gives the lawyer a final chance to persuade the trial judge to reconsider their decision and allow the evidence.
2. More importantly, it creates a clear record for a potential appeal. If the case is later appealed to a higher court, the appellate judges can review the "offer of proof" to determine if the trial judge's decision to exclude the evidence was a legal error that might have affected the trial's outcome. Without an offer of proof, it can be very difficult for an appellate court to understand what evidence was excluded and why its exclusion might have been significant.

Examples:

• Witness Testimony (Relevance):

  In a defamation lawsuit, the plaintiff's lawyer calls a witness to testify about a conversation they overheard where the defendant allegedly made a defamatory statement. The opposing counsel objects, arguing the conversation is "hearsay" and "irrelevant" because the third party involved is not part of the lawsuit. The judge sustains the objection, preventing the witness from sharing the details of the conversation.

  The plaintiff's lawyer then requests an offer of proof. Outside the jury's presence, the lawyer explains to the judge that the witness would testify that the defendant explicitly admitted to spreading false rumors about the plaintiff during that conversation. The lawyer argues this testimony is crucial to prove the defendant's intent and knowledge of falsity, which are key elements of defamation, and that it falls under an exception to the hearsay rule.

  This illustrates an offer of proof because the lawyer is formally stating what the excluded testimony would have been, why it's relevant to the case (proving intent), and why it should be admissible, thereby preserving the issue for potential appeal.

• Document (Authentication):

  During a breach of contract trial, the plaintiff's lawyer attempts to introduce an email from the defendant that seemingly confirms the terms of an oral agreement. The defendant's lawyer objects, claiming "lack of foundation" because the plaintiff's lawyer hasn't sufficiently proven that the email actually came from the defendant. The judge agrees and sustains the objection, preventing the email from being shown to the jury.

  The plaintiff's lawyer then makes an offer of proof. They explain to the judge that if allowed, they would have called a forensic IT expert to testify that the email originated from the defendant's specific IP address and contained digital signatures consistent with the defendant's known email patterns. They argue this would properly authenticate the email and demonstrate its critical relevance to proving the contract's terms.

  Here, the offer of proof details the content of the excluded evidence (the email) and outlines the additional steps the lawyer would have taken to establish its admissibility (expert testimony for authentication), ensuring the appellate court understands the significance of the excluded document.

• Expert Opinion (Methodology):

  In a product liability case involving a defective medical device, the plaintiff's lawyer calls an engineering expert to testify that a specific design flaw in the device caused the plaintiff's injury. The defense counsel objects, arguing the expert's methodology for linking the design flaw to the injury is not scientifically reliable and therefore inadmissible. The judge sustains the objection, preventing the expert from offering that specific opinion.

  The plaintiff's lawyer then makes an offer of proof. They explain that the expert would have detailed a series of peer-reviewed studies and industry-standard simulations that support their conclusion regarding the design flaw's causal link to the injury. The lawyer emphasizes that this testimony is essential for the jury to understand the technical aspects of the defect and its impact.

  This example demonstrates an offer of proof where the lawyer explains the substance of the expert's excluded opinion and provides the underlying scientific basis and methodology that they believe makes the opinion admissible, creating a record for appellate review of the judge's decision.