I am Bill Hartzer, and I serve as an SEO expert witness, a search engine optimization expert witness, in civil matters where the disputed facts live in search results, web analytics, server logs, and the history of a website. I have worked in search since 1996, I have been retained as a testifying expert for more than eight years, and I have testified at trial in United States Federal District Court and in the Grand Court of the Cayman Islands. I work for plaintiffs and for defendants, and I write rebuttal reports against other experts in this field.
My job is not to argue that a party did good or bad SEO. It is to establish what changed on a website, when it changed, what caused the change, and what can be proven from the surviving data, and then to defend that opinion in a written report, in deposition, and at trial.
Testimony record
- Working in search since 1996, before Google existed
- 38 expert reports and rebuttal reports
- 9 depositions
- 5 trials and 1 arbitration
- State, federal, and international proceedings
- Retained by plaintiffs and by defendants in roughly equal measure
The list of matters in which I testified at trial or by deposition during the previous four years, as Federal Rule of Civil Procedure 26(a)(2)(B)(v) requires, is provided on retention together with a full curriculum vitae and the ten-year publication list required by Rule 26(a)(2)(B)(iv).
What an SEO expert witness does
An SEO expert witness analyzes search engine data, web analytics, server logs, and the recorded history of a website in order to establish disputed facts: what a website or a search result looked like on a given date, what changed and when, what caused a change in rankings or traffic, and whether a party’s technical work met the standard a competent practitioner would have applied at the time. The work product is a written report under Rule 26, followed where necessary by deposition and trial testimony.
The work is factual and methodological, not advocacy. Search disputes almost always reduce to one of four questions, and it is worth being precise about which one you are asking, because each requires different evidence and a different method.
Causation. Traffic or rankings fell. Did the defendant’s conduct cause the fall, or did something else? This is the hardest question in the discipline and the one most often answered badly. I describe my approach on the SEO damages and lost traffic analysis page.
Standard of care. Did an agency, a developer, or an in-house team do what a competent practitioner would have done at the time, judged by the standards that existed on the date of the conduct rather than by today’s standards.
Attribution and reconstruction. What did this website, this page, or this search result look like on a particular date, and who controlled it? This is forensic work, and it is frequently the entire case.
Valuation. What was the search visibility of a domain, a page, or a brand worth, and what remains of it? I establish the traffic and visibility counterfactual. I do not convert it into dollars; that belongs to a CPA or an economist who takes my traffic delta as a stated assumption.
An expert who cannot say which of these four questions he is opining on, and which he is deliberately not opining on, is an expert who is about to be excluded.
The disputes where search evidence decides the outcome
These are the matters in which I am most often retained. The pattern across all of them is the same: a party asserts that something happened to a website’s visibility, and the only reliable record of it is technical.
| Matter type | What the expert is establishing |
|---|---|
| Traffic loss and business damages | Whether an identified decline is attributable to the conduct at issue rather than to a Google algorithm update, seasonality, competitor action, or the party’s own changes |
| SEO malpractice and agency contract disputes | What competent practice required on the dates of the conduct, what was delivered against what was contracted, and whether the work caused the harm claimed |
| Defamation and negative search results | Prominence and persistence of the material for identified queries over time, reconstructed from dated evidence rather than from a screenshot taken last week |
| Trademark and keyword advertising | Whether a mark was used to divert search demand, in organic results or in paid placement, and what the diversion consisted of |
| Domain name disputes | The search visibility, history, and acquired value attached to a domain name |
| Site migrations and redesigns | Redirect mapping, indexation, and whether the loss was foreseeable and preventable at the time of launch |
| Google penalties and negative SEO | Whether a manual action or an external link campaign occurred, who benefited, and whether it plausibly caused the alleged effect |
| E-commerce and local search visibility | Category and product-level indexation, Google Business Profile control, and revenue exposure by page cohort |
The standard the testimony has to meet
Federal Rule of Evidence 702 was amended effective December 1, 2023. The proponent must now demonstrate that it is more likely than not that the opinion rests on sufficient facts or data and reflects a reliable application of the method. Search opinions are exposed in exactly those two places.
Under Rule 702(b), much of what circulates as SEO evidence is not measurement. Third-party rank trackers, keyword volume figures, and traffic estimates from commercial tools are modeled numbers derived from proprietary panels. They are useful for orientation and a weak foundation for an opinion when the party’s own Google Search Console exports, analytics, and raw server logs exist and were not used. Where I rely on a third-party estimate, I say so, and I say what it cannot support.
Under Rule 702(d), the characteristic SEO overstatement is the causal leap: rankings fell after the defendant acted, therefore the defendant caused the fall. The correlation of two timelines is a real method. Causation is a conclusion that method does not reach on its own.
Because search expertise is technical and experience-based rather than scientific, Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999), rather than Daubert alone supplies the framework. Thirty years of experience is a qualification. It is not a methodology. What survives scrutiny is a documented, reproducible protocol: stated data sources, stated date ranges, stated exclusions, stated controls for confounding causes, and crawls and queries that another competent analyst could re-run. I cover the rules and the case law in more depth on the legal and evidentiary standards for SEO expert witness work page.
How I work
The first call is a conflict check and a short conversation about what the dispute actually turns on. It costs nothing and it is frequently the most useful half hour in the matter, because a meaningful share of prospective search cases end there: the data is gone, or it never supported the theory, and it is better to learn that before a complaint is drafted than during a deposition.
I prefer to start as a consulting expert. Under Rule 26(b)(4)(D), a retained expert who is not expected to testify is ordinarily beyond discovery. The early work in a search matter, crawling the site, pulling what analytics and log data survive, and reconstructing the timeline, is classic consulting work, and it is frequently the work that tells you whether there is a case. I would rather do that first and be designated afterward.
I pull the data myself from first-party sources wherever it still exists: Google Search Console, Google Analytics, Bing Webmaster Tools, raw server and CDN logs, CMS revision history, and full crawls of the site. Third-party indexes from Semrush, Ahrefs, and Majestic corroborate; they do not substitute. Contested web material is captured forensically with a SHA-256 hash computed at the moment of capture so that it can be authenticated under Rules 901 and 902.
I keep an ordered work log of everything considered, because Rule 26(a)(2)(B)(ii) says considered, not relied upon, and I produce it.
I write the report to be read. Judges and juries do not need to understand how Google works. They need to understand what changed, when, and how I know. The SEO expert testimony page describes what my reports and rebuttal reports contain, how I prepare for deposition and trial, and the cross-examination questions an SEO expert should be ready to answer.
Preserve the evidence before it deletes itself
The single most avoidable failure in search litigation is that the best evidence expires on a timer while everyone is still exchanging letters. Google Search Console retains performance data for roughly sixteen months on a rolling basis. Google Analytics 4 purges event-level data on a default retention schedule. Server and CDN logs are commonly rotated within 30 to 90 days. A redesign destroys the site as it existed. None of that requires bad faith, and under Rule 37(e) the most severe sanctions require intent to deprive, so the data is simply gone.
If you are sending a preservation letter, name the specific data sources that are about to expire. Most preservation letters do not, and I am glad to review one before it goes out.
Qualifications
I have worked in search engine optimization since 1996, first in-house as the SEO and webmaster at an international telecommunications software company running multilingual websites, and since then as a consultant through Hartzer Consulting. I still run search work for clients today, which is the reason I can speak to current practice rather than to practice as it stood when I stopped doing it.
My consulting work covers technical SEO audits, site architecture, website and domain migrations, international search, link analysis, Google penalty and recovery work, paid search, web analytics, and the domain name system. It is the combination, rather than any one discipline, that most litigation needs. I have spoken at Pubcon, SMX, and State of Search, I have been cited in Search Engine Land, Moz, and Search Engine Journal, and I founded the Dallas/Fort Worth Search Engine Marketing Association in 2004.
Related expert witness practices are described on their own pages: Google Ads and PPC expert witness, online advertising expert witness, web analytics and web traffic expert witness, domain name expert witness, social media expert witness, and digital marketing expert witness. A deeper reference on search evidence, the rules, and the case law is maintained at searchengineoptimizationexpertwitness.com.
Engaging me as an SEO expert witness
Fees are hourly against a retainer, set out in an engagement letter, with separate rates for deposition and trial days. Under Rule 26(b)(4)(E) the party taking an expert’s deposition ordinarily pays the expert’s reasonable fee for the time spent responding. Cost is driven mainly by data volume, the number of URLs, the length of the period at issue, and how much of the record survives, rather than by the size of the claim.
Bill Hartzer, Hartzer Consulting
Telephone: 214-236-4378
Email: [email protected]
Attorneys evaluating any expert in this discipline may want the 13-point SEO expert witness qualification guide, the questions worth asking any candidate in this field, including the ones I would want asked of me.
Attorneys preparing to retain an expert can start with the internet expert witness resources for attorneys, which include a retainer template and evidentiary standards.
Frequently asked questions
What does an SEO expert witness do?
An SEO expert witness analyzes search engine data, web analytics, server logs, and the recorded history of a website to establish disputed facts: what a site or a search result looked like on a given date, what changed and when, what caused a change in rankings or traffic, and whether a party’s technical work met the standard a competent practitioner would have applied at the time. The work product is a written report under Rule 26, followed where necessary by deposition and trial testimony.
Is SEO expert testimony admissible?
Yes, subject to the same gatekeeping every technical expert faces. Because search expertise is technical and experience-based rather than scientific, Kumho Tire rather than Daubert alone supplies the framework. Since the December 2023 amendment to Rule 702, the proponent must show by a preponderance that the opinion rests on sufficient facts or data and reflects a reliable application of the method. What gets excluded is not SEO testimony as a category; it is opinions that outrun their own method, most commonly by asserting causation on the strength of two timelines that happen to line up.
How is lost search traffic converted into damages?
In two stages, by two different experts. I establish the counterfactual, what traffic or visibility would have been absent the conduct, with controls for algorithm updates, seasonality, competitor activity, and demand shifts, and I state the confidence and the limits of that estimate. A financial expert then takes that delta as an assumption and converts it into revenue and incremental profit. A single expert who does both invites an attack on the weaker half that takes the whole opinion down.
Can screenshots and Internet Archive pages be used in court?
They can be, with a foundation. Archived material has been admitted since at least 2004, usually on testimony or an affidavit from someone with knowledge of how the archive captures and stores pages. The recurring failures are date imprecision and captures whose scope the witness cannot vouch for. A contemporaneous forensic capture with a hash computed at capture time is a stronger exhibit than an archive snapshot retrieved later.
Do you work for plaintiffs or defendants?
Both, in roughly equal measure, and I take rebuttal assignments against other experts in this discipline. An expert who only ever appears on one side is being retained for his conclusions rather than his method, and it shows on cross-examination.
What does an SEO expert witness cost?
Fees are hourly against an initial retainer, with separate day rates for deposition and trial, set out in an engagement letter once scope is defined. Cost is driven mainly by data volume and by how much of the record survives rather than by the size of the claim.
When should an SEO expert be brought in?
Before the preservation letter goes out, if that is possible, because the letter should name the specific data sources that are about to expire. Failing that, before the theory of the case hardens. The most expensive mistake in this field is discovering in expert discovery that the data never supported the claim.
This page describes the evidentiary environment in which I work and the standards my testimony has to meet. It is general information about my practice, not legal advice, and nothing on it creates an expert or consulting engagement.