Daubert Challenges in Search Cases

What the motion is really attacking

A motion to exclude a search expert almost never argues that search analysis is an illegitimate field. That argument would fail, and a sophisticated opponent knows it. The motion argues something narrower and harder to answer: that this witness, in this report, stated a conclusion the underlying work cannot support.

The distinction determines what defends the opinion. A defense organized around the legitimacy of the discipline — search engines are real, visibility has value, these methods are common — misses what is being challenged: the distance between the analysis performed and the sentence written at the end of it.

That distance is where this field is characteristically weak. The technical work is often good: someone crawled the site, pulled the logs, reconstructed the redirect map, and found real defects. Then the report says the defects caused a stated dollar loss, and nothing between the crawl and the dollar figure establishes the link. The motion writes itself — and after the December 2023 amendment to Rule 702, the answer that the gap goes to weight rather than admissibility is much weaker than it was.

When it arrives and what the court decides

The challenge is a pretrial motion, filed on the schedule the court's order sets, usually with the motions in limine. By then the record for deciding it is closed: the expert's report, the materials the expert considered, and the deposition transcript. Most exclusion motions are won or lost in the deposition, months before anyone writes a brief.

The court decides under Rule 104(a), by a preponderance, with the burden on the party offering the opinion. An evidentiary hearing is discretionary; many courts decide on the papers, and a proponent should not plan on a hearing as the place to cure a defect.

What the court applies is the amended Rule 702 text and the framework of Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), extended to technical and other specialized knowledge by Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999). Daubert directed attention to methodology rather than to the conclusions it generates; the 2023 amendment to subsection (d) closed part of the gap that framing opened.

The one reported ruling on a search expert

Reported decisions applying Daubert to an SEO expert are scarce. The one that exists is Campmor, Inc. v. Brulant, LLC, No. 2:09-cv-05465 (D.N.J. Apr. 23, 2013) (ECF No. 111), and the motion to exclude was denied. Campmor had retained Brulant to rebuild its e-commerce site; after the 2009 launch it alleged lost search visibility and terminated. Its expert opined that the work failed industry practice, relying in part on a third-party SEO audit by another firm and on the engine's published optimization guide. The opinion is on Justia. Two grounds were raised; both recur.

Reliance on another firm's audit. The court held the audit data was not so unreliable that the expert's testimony had to be excluded, and that an expert need not perform independent testing where the underlying data is reasonably reliable. That is narrower than it is often reported: it addresses whether reliance on another's work is categorically disqualifying, not whether a particular report is dependable.

The date of the standard. The expert cited the 2010 edition of the guide when the conduct ended in 2009, the 2008 edition being the contemporaneous one. The court rejected the objection — but on expressly comparative reasoning: it reviewed both editions, found little substantive difference, and characterized the changes as non-material additions rather than changes to fundamental principles.

That nuance should not be flattened, and I would not flatten it in my own favor. Campmor is not authority that measuring old conduct against current guidance is fine. It holds that where two editions do not materially differ on the point at issue, the date is not fatal. Guidance has changed substantially since, so on many issues the same reasoning now cuts the other way.

What the damages exclusions teach

The instructive law is not in search cases. It is in the damages exclusions, where the failure mode is identical: a model that omits what everyone agrees it should have accounted for.

Concord Boat Corp. v. Brunswick Corp., 207 F.3d 1039 (8th Cir. 2000). The Eighth Circuit held that the plaintiffs' economist's econometric model should not have been admitted because it did not incorporate all aspects of the economic reality of the market: it ignored inconvenient evidence and failed to account for market events both sides agreed were unrelated to any anticompetitive conduct. Without that testimony the verdict was speculative. The search analogue is exact — a before-and-after model that does not account for a concurrent core update, a migration, or a competitor's move is the Concord Boat failure.

LifeWise Master Funding v. Telebank, 374 F.3d 917 (10th Cir. 2004). The Tenth Circuit affirmed exclusion of an "S-curve" growth model that was not in regular usage for predicting future profits, was not peer reviewed, had no uniform usage in any industry, and was capable of manipulation to achieve virtually any desired result. Describe this one accurately: the witness was LifeWise's own chief executive officer, not a retained expert, and he was also held unqualified — he had never used the methodology, had taken no accounting or finance courses, and had no training in damages analysis. That combination is a sharper warning for a party thinking of proving loss through its own marketing director.

Zenith Electronics Corp. v. WH-TV Broadcasting Corp., 395 F.3d 416 (7th Cir. 2005). Exclusion affirmed, and the company's own internal projections rejected as a substitute. The language is the most quotable in this area: a witness who invokes "my expertise" rather than analytic strategies widely used by specialists is not an expert as Rule 702 defines that term; nothing in Daubert or the Rules requires a court to admit opinion evidence connected to existing data only by the ipse dixit of the expert; and reliable inferences depend on more than say-so, whether the speaker is a manager or a putative expert.

The grounds that actually get raised

The arguments against a search expert cluster. These are the ones I see, roughly in order of how often they land:

• Data provenance. A quantified loss built on third-party estimates when the party's own Search Console, analytics, and log data existed and were producible.
• Unaddressed confounds. A core update, a seasonality effect, a competitor's launch, or a tracking change in the same window, unmentioned in the report.
• The causal leap. Two aligned timelines offered as proof of causation, with no elimination work behind them.
• The date of the standard. Conduct from one year measured against guidance published later, without comparing the versions.
• Scope beyond qualification. A technical witness computing lost profits or valuing a business.
• Undisclosed exclusions. Filters, removed segments, and dropped date ranges that first surface in deposition.
• Irreproducibility. Charts whose underlying exports were not produced, or whose numbers cannot be regenerated from what was.
• Sponsored tool output. A vendor's score or index adopted as a finding, with no account of how the vendor computes it.

Note how many are drafting failures, not analytical ones. I have read reports whose underlying work was sound and whose exposure came entirely from what the author never wrote down.

The record that defeats the motion

The defense is assembled before the report is served, because after service the record is fixed and anything added later looks like repair work.

Three habits do most of the work. State the method before the conclusion, in enough detail that the conclusion reads as the output of the stated steps rather than as an assertion the steps were assembled to support. Address the alternatives in the report, including the ones that hurt: name the update that landed in the window, state what was examined to test whether it explains the decline, and state the result even where the result is that it partly does. Produce the working material — raw exports, crawl files, log extracts — so reproducibility is a fact the other side can verify rather than a claim to accept.

The deposition is the other half. An expert who has documented the protocol answers the standard sequence — what did you look at, over what period, what did you exclude, what else could explain it, can I reproduce it — from the report. One who has not improvises, and the improvisation becomes the brief's best exhibit.

What exclusion looks like, and the lesser outcomes

Wholesale exclusion is the outcome parties imagine and it is not the common one. The frequent results are partial: a court leaves the technical findings standing and strikes the causal attribution, or admits causation and excludes the quantified loss, or admits the opinion while barring a particular chart.

That has a structural implication. Where the technical and economic opinions live in one narrative in which every conclusion depends on the same chain, a defect anywhere threatens all of it. Where the technical findings stand on their own data — this many URLs left the index on this date, these redirects resolved to a 404 — and the economic consequences are handled by a damages expert taking those findings as inputs, a ruling against the second does not automatically reach the first.

Reading the other side's report

Whether a challenge is worth bringing is a judgment for counsel, informed by someone who can work the other expert's data rather than only read the prose. The questions that decide it are mechanical.

1. Is every number traceable to a produced file, and does the file produce the number?
2. Are the date ranges stated, and is the comparison period defensible or merely convenient?
3. Do the stated exclusions account for the difference between the report's figures and the raw exports?
4. Did anything else happen in the window — an update, a season, a competitor, a deployment — and does the report acknowledge it?
5. Does the opinion stay inside the pages, queries, and period the data actually covered?
6. Where a third-party score or index appears, does the report explain how it is computed?

A rebuttal that answers those questions with the opposing expert's own production is a different document from one that disagrees in the abstract, and it is the version that supports a motion. Where they come back clean, the better use of resources is usually cross-examination on scope rather than a motion that hands the other side a favorable reliability ruling before trial.

Frequently Asked Questions

Published 2026-08-11