Insights
Sargon, Frye and Brown/O'Key: how three neighbouring states judge the same expert
An expert who is admissible in Portland is not automatically admissible in Sacramento, and the report that survives in Seattle may be attacked on different ground in Los Angeles. California, Washington and Oregon each apply a different test to expert testimony in their state courts, while all three sit in a single federal circuit applying a fourth.
Why does this matter before the report is written?
Because the four standards reward different things. A report drafted for a reliability-focused gatekeeping analysis emphasises the inferential steps; one drafted for a general-acceptance test emphasises the standing of the method. Drafting for the wrong forum produces a report that is defensible on its own terms and vulnerable on the ones that will actually be applied.
The practical error is rarely a wrong conclusion. It is an emphasis mismatch: an expert spends four pages establishing that a technique is universally accepted in a forum that does not ask that question and half a paragraph on the analytical gap the court is actually directed to examine.
The four frameworks below are the ones that govern in this region. Which applies to a particular matter depends on the forum and, in some cases, on whether the technique at issue is treated as novel — questions for counsel rather than determinations this site makes.
California: Sargon and Evidence Code sections 801 and 802
California asks whether the reasoning bridges the gap between the material relied on and the conclusion drawn. Under Sargon Enterprises v. USC (2012) the trial court acts as a gatekeeper examining the basis of the opinion under sections 801 and 802, without weighing which of several reasonable conclusions is correct.
The distinctive feature is where the challenge lands. California exclusion motions rarely succeed by arguing that the expert is unqualified. They succeed by arguing that the reasoning does not survive contact with the record — a causation opinion citing literature about a different exposure, a damages model projecting from a baseline the documents do not show, an assumed fact no witness established.
Section 802 matters more than its profile suggests, because it permits the court to examine the expert about the basis of an opinion, and section 402 provides a mechanism for taking that evidence outside the jury's presence. The gatekeeping is therefore not confined to the papers.
The report that does well here states the records relied on, names the method, sets out the inferential steps in sequence, and acknowledges the limits of what the evidence supports. An expert who concedes those limits in writing is markedly harder to dismantle than one conceding them for the first time on cross-examination.
Washington: ER 702 and the Frye general-acceptance test
Washington evaluates expert testimony under ER 702 and applies the Frye general-acceptance test to novel scientific evidence. Frye asks whether the theory or technique has achieved general acceptance in the relevant scientific community — a question about the standing of the method rather than the rigour with which this expert applied it.
That is a genuinely different inquiry from the federal one, and the difference cuts both ways. A well-established method carelessly applied is less exposed under Frye than under Daubert. A carefully applied novel method is more exposed.
For most clinical, financial and custom-and-practice testimony the distinction is academic, because none of it is novel science. It becomes decisive where a causation theory depends on a mechanism that is contested within the literature, or on a methodology that has not achieved settled acceptance.
The drafting consequence follows directly: where a Washington opinion rests on an accepted method, establish the acceptance explicitly rather than assuming it. Where it rests on something more contested, say so in the report.
Oregon: OEC 702 through State v. Brown and State v. O'Key
Oregon evaluates expert and scientific evidence under OEC 702 through the framework the Oregon Supreme Court developed in State v. Brown and refined in State v. O'Key. It is related to the federal inquiry but not identical with it, and it is distinct again from Washington's Frye test.
Oregon's framework is the least familiar of the three to out-of-state counsel, largely because it is frequently mischaracterised as either Daubert or Frye when it is neither. An expert who arrives assuming Daubert applies in Multnomah County has assumed something the forum does not.
The practical drafting posture is to address both the standing of the method and the rigour of its application rather than choosing between them — which is, in any event, what a thorough report should do.
Federal: FRE 702 and the Daubert line, across all three
Every federal matter in California, Washington and Oregon is governed by Federal Rule of Evidence 702 as amended in December 2023 and the Daubert line of authority, with appeals to the Ninth Circuit. This is why a federal case in Portland resembles a federal case in San Diego far more than it resembles a state case across the street.
The December 2023 amendment to Rule 702 clarified the proponent's burden and the court's role in examining whether the opinion reflects a reliable application of the methodology to the facts. Its practical effect has been to make the application question — not merely the method question — squarely part of the admissibility analysis.
The federal report obligation differs as much as the standard. A report under FRCP 26(a)(2)(B) is a signed, self-contained document stating the opinions, the facts considered, exhibits, qualifications, prior testimony and compensation. State-court disclosure instruments in all three states are different in kind, and serving one where the other is required is a recurring source of avoidable motion practice.
What this means in practice
Establish the forum before the expert begins substantive work, not after. Removal is the case that most often catches people out, because the standard and the report obligation both change while the underlying analysis does not.
Where removal is realistically in prospect, the sensible course is to build the report to the more demanding of the two obligations from the outset. A Rule 26(a)(2)(B)-grade report is always adequate in state court; the reverse is not true.
Where a matter is firmly in state court, drafting to that state's emphasis is worth doing deliberately rather than by default. It is a small amount of additional thought at the outset and it is the difference between a report that answers the question the court will ask and one that answers a neighbouring question well.
Frequently Asked Questions
California state courts do not. They apply the gatekeeping analysis described in Sargon Enterprises v. USC under Evidence Code sections 801 and 802, with the Kelly standard governing novel scientific technique. Federal matters in California are governed by FRE 702 and the Daubert line.
Washington state courts evaluate expert testimony under ER 702 and apply the Frye general-acceptance test to novel scientific evidence. Federal matters in the Western or Eastern District of Washington are governed by FRE 702 and Daubert.
Not in circuit court. Oregon applies OEC 702 through the framework developed in State v. Brown and refined in State v. O'Key, which is related to but not identical with the federal inquiry. District of Oregon matters are governed by FRE 702 and Daubert.
The admissibility standard changes to FRE 702 and the Daubert line, and the disclosure instrument changes to a signed, self-contained Rule 26(a)(2)(B) report. The substantive analysis usually survives intact, but the document may have to be rebuilt.
In practice, yes — a report that states the records relied on, names and justifies the method, sets out the inferential steps, and acknowledges its own limits does well under all four. Building to the most demanding applicable obligation is the reliable approach where the forum may change.
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