Oregon Expert Witness Rules: What Litigators Need to Know

Expert witness testimony in Oregon civil litigation is governed by a blend of procedural mandates and evidentiary standards rooted in the Oregon Rules of Civil Procedure (ORCP) and Oregon Evidence Code (OEC). While Oregon maintains a relatively flexible disclosure process, the admissibility of expert opinion is subject to a Daubert-like reliability test and must be disclosed with sufficient detail during discovery. In malpractice, construction, and complex tort cases, expert compliance is often the key to trial eligibility and evidentiary admissibility.

Designation Requirements

Oregon does not require a formal motion to designate expert witnesses. Instead, experts are disclosed through interrogatory responses and subject to the state's liberal discovery rules. Under ORCP 36 B(1) and ORCP 36 B(4), any party may obtain discovery of:

• The identity of any expert who may testify at trial
• The subject matter of the expert’s testimony
• The substance of facts and opinions to be offered
• A summary of the grounds for each opinion

Disclosures must comply with the court’s pretrial scheduling order, which typically sets deadlines for initial and rebuttal expert information. Failure to identify an expert or to timely disclose the basis of their opinion can result in exclusion under ORCP 46, which governs sanctions for discovery violations.

Expert Disclosure Process

Oregon’s expert exchange process is less formal than the federal model but still requires substance and timeliness. There is no statewide requirement for written expert reports, but parties may request such reports through requests for production or by stipulation. Discovery of expert opinions is primarily conducted through:

• Written interrogatories
• Expert depositions
• Pretrial discovery conferences

Under ORCP 36 B(4) and ORCP 55, parties may obtain information about:

• The expert’s qualifications and experience
• The methodologies used
• Documents, literature, or studies reviewed
• The expert’s compensation arrangements

If the expert has testified in other litigation, prior deposition transcripts and opinions may be discoverable as well. Courts may order production of additional materials or reports on a case-by-case basis, particularly in complex or technical matters.

Required Declarations

Oregon does not mandate expert declarations during standard disclosure. However, declarations or affidavits become critical at the summary judgment stage, governed by ORCP 47 D. Any expert affidavit submitted to support or oppose summary judgment must:

• Be based on personal knowledge
• Set forth facts admissible in evidence
• Establish the expert’s competency and qualifications
• Explain the basis and methodology for their opinions

Courts routinely reject conclusory expert statements that lack foundational explanation. In professional negligence or products liability cases, failure to provide an admissible expert declaration often results in dismissal of the claim.

In medical malpractice actions, plaintiffs must establish breach and causation through expert opinion unless the negligence is obvious. Expert declarations are typically required to meet this burden at the pretrial phase.

Fees and Compensation

Oregon law permits experts to be compensated for their time and expertise, but the requesting party—typically the one seeking a deposition—must pay a reasonable fee. This principle is derived from general practice, as there is no specific ORCP provision on expert compensation.

Disputes regarding expert witness fees are resolved by the court, which considers:

• The expert’s credentials
• Time spent reviewing and preparing
• Prevailing market rates for the field
• Necessity and reasonableness of the work performed

Preparation time may also be compensable, particularly in technical cases requiring substantial review of materials.

Discovery Scope and Limitations

Expert discovery in Oregon is governed by ORCP 36 B(4) and follows these key principles:

• Parties may obtain full discovery of testifying experts
• Discovery includes the expert’s opinions, methodologies, and factual bases
• Parties may also depose experts and request materials relied upon

However, Oregon restricts discovery of non-testifying consultants—experts retained solely for litigation preparation but not expected to testify. These experts are shielded from discovery unless exceptional circumstances justify access (e.g., facts unavailable elsewhere).

Draft reports and communications between counsel and experts are not automatically protected, as Oregon has not adopted the 2010 federal amendments to Rule 26. Work-product protections may still apply, but attorneys should proceed cautiously when sharing sensitive material.

Admissibility Standards

Oregon applies a Daubert-like standard for expert admissibility under OEC 702, interpreted through State v. Brown, 297 Or. 404 (1984), and subsequent rulings such as Marcum v. Adventist Health System/West, 345 Or. 237 (2008). Under this framework, expert testimony is admissible if:

1. The witness is qualified by knowledge, skill, experience, training, or education
2. The testimony assists the trier of fact
3. The opinion is based on scientific, technical, or other specialized knowledge
4. The underlying methodology is reliable and relevant

Oregon trial courts serve as gatekeepers, especially in cases involving novel science or complex causation. The Brown/Marcum standard allows courts to evaluate:

• General acceptance in the scientific community
• Whether the technique has been subject to peer review
• The expert’s ability to apply the method reliably
• Whether the methodology is testable or falsifiable

Motions to exclude experts for lack of reliability are common in cases involving engineering, medicine, toxicology, and financial analysis.

Key Deadlines & Strategy Notes

Expert disclosure deadlines in Oregon are typically set by Uniform Trial Court Rules (UTCR) or by a case-specific pretrial order. Standard timelines include:

• Initial expert disclosures: Often 60–90 days before trial
• Rebuttal experts: Typically disclosed 30 days after initial disclosures
• Daubert motions or motions in limine: Filed per pretrial schedule, often 30–45 days before trial
• Summary judgment declarations: Must comply with ORCP 47 D and include detailed expert support

In medical negligence and professional liability cases, attorneys should prepare expert declarations well before summary judgment deadlines. Oregon courts expect clear articulation of scientific methodology, not just conclusions.

State-Specific Statutes & Local Rules

• ORCP 36 B(4): Governs expert witness discovery
• ORCP 47 D: Summary judgment affidavit requirements
• OEC 702: Daubert-like standard for admissibility
• State v. Brown, 297 Or. 404 (1984): Key case on expert reliability
• Marcum v. Adventist Health, 345 Or. 237 (2008): Reinforces Oregon’s gatekeeping duty

Local rules, especially in Multnomah, Washington, and Lane counties, may add specific requirements for disclosure formats, deadlines, or Daubert motion practice. Practitioners should consult judge-specific scheduling orders for final deadlines and procedural expectations.