Expert Witnesses in Washington
According to Washington Rule of Evidence (ER) 702, an expert witness is someone qualified by knowledge, skill, experience, training, or education to give opinion testimony that helps the judge or jury understand evidence or determine a fact at issue.
Rules Governing Disclosure
Governing Authority: Civil Rule 26(b)(5)
In Washington State Superior Court, discovery of expert witnesses is governed primarily by Civil Rule (CR) 26(b)(5). Washington does not require automatic expert reports like Federal Rule 26(a)(2), but it does require meaningful disclosure upon proper request and pursuant to the court’s scheduling order. It should be noted that expert witness reports are not universally mandated by state law for every case in Washington.
Under CR 26(b)(5)(A), a party may obtain discovery concerning experts expected to testify at trial. The rule requires disclosure of core identifying and opinion information sufficient to allow the opposing party to prepare for cross-examination and rebuttal.
The required disclosure includes:
The identity of each expert expected to testify at trial
The subject matter on which the expert will testify
The substance of the facts and opinions to which the expert is expected to testify
A summary of the grounds for each opinion
Although Washington does not mandate a detailed written expert report in every case, the summary must be sufficiently complete to prevent unfair surprise and allow meaningful preparation.
Non-Testifying Experts
Discovery of experts retained or specially employed in anticipation of litigation but not expected to testify at trial is significantly restricted. Under CR 26(b)(5)(B), such discovery is permitted only:
Upon a showing of exceptional circumstances making it impracticable to obtain the information by other means
An important exception applies to experts conducting court-ordered physical or mental examinations under CR 35, where reports must be disclosed under specified conditions.
Admissibility Standards
In Washington, expert admissibility is governed by a combined Frye and ER 702 framework. Under ER 702, expert testimony is admissible if the witness is qualified by knowledge, skill, experience, training, or education and the testimony will assist the trier of fact. If the testimony involves novel scientific evidence, courts apply the Frye test, which requires that the scientific theory or methodology be generally accepted in the relevant scientific community.
If the evidence is not novel, Frye does not apply, and the court evaluates admissibility under ER 702 and general evidentiary principles, including ER 403. Unlike federal courts, Washington has not adopted a full Daubert reliability analysis for all expert testimony.
Attorney–Expert Communication Protection
In Washington state court, attorney–expert communications are protected primarily through the work-product doctrine under Civil Rule 26(b)(4) and CR 26(b)(5), rather than through a separate, automatic expert-report privilege like in federal court.
For testifying experts, Washington does not provide blanket protection for all communications with counsel. Materials that an expert considers or relies upon in forming opinions are generally discoverable, even if those materials originated from the attorney. This means drafts, data, and information that influence the expert’s opinions may be subject to discovery. However, pure attorney mental impressions, legal theories, and litigation strategy remain protected as opinion work product unless they are directly injected into the expert’s analysis.
For non-testifying (consulting) experts, communications are more strongly protected. Under CR 26(b)(5)(B), facts known or opinions held by an expert retained in anticipation of litigation but not expected to testify are discoverable only upon a showing of exceptional circumstances, making their communications with counsel largely shielded.
Compensation
Washington requires reasonable compensation for expert time spent responding to discovery. Unless manifest injustice would result, the court shall require the party seeking discovery to:
Pay a reasonable fee for the expert’s time in deposition or responding to discovery
Potentially pay a fair portion of the opposing party’s expenses incurred in obtaining expert facts and opinions
This ensures that expert discovery does not impose unfair financial burdens.
State-Specific Statutes & Local Rules
CR 26(b)(5): Governs expert discovery, including scope and compensation
CR 37: Provides for sanctions and preclusion for failure to disclose experts
ER 702: Admissibility of expert testimony
