Disclaimer

General reference, not legal advice

trialwitness.com is a general reference on expert witnesses, expert testimony and the framework governing the admissibility of opinion evidence. Everything on it is published for general information.

It is not legal advice. It does not consider any reader’s facts, jurisdiction, procedural posture, scheduling order or the record in any case, and each of those changes the answer to nearly every question discussed here. A page describing what a rule requires is not telling any particular reader what to do about a particular matter, and it should not be read as if it were.

Anyone facing a live question about expert testimony should take advice from counsel admitted in the relevant jurisdiction who knows the matter. That is not a disclaimer written to be ignored: the number of variables that change an answer in this area — forum, standard, scheduling order, the state of the record, the identity of the judge — is large enough that general material can only ever be a starting point.

Not an opinion on anyone’s matter

No page here is an expert opinion, and nothing on this site should be cited as one. An expert opinion is formed on a specific record, by a person who has examined it, subject to disclosure obligations and to cross-examination. General published commentary has none of those properties.

Nor is anything here an assessment of any identified expert, report, method or motion. The site describes categories of failure that appear in reported decisions and categories of question that arise in practice; it does not evaluate any real witness or any real filing.

Reading this site creates no engagement

Reading these pages, quoting them, or writing through the contact page creates no engagement, no retention, and no professional or confidential relationship with Hartzer Consulting.

An engagement begins only where a conflict check has cleared and terms have been agreed in writing. Before that point there is no relationship to protect information, which is why the contact page asks that a first message describe a matter in general terms and carry nothing privileged, confidential or subject to a protective order.

Jurisdiction matters more than most summaries admit

Much of the material here describes federal practice, and federal practice is not national practice. State courts apply their own admissibility standards, several of which differ substantially from the federal rule and from each other, and some states never adopted federal protections that practitioners routinely assume to be universal.

Within the federal system, questions of real practical consequence remain split — among them whether an expert’s deposition preparation time is shifted to the party taking the deposition, and how forgiving the sanctions test for a late disclosure is. Those splits are reported on the pages that discuss them, and they mean that a correct statement about one district can be a wrong statement about the next.

Rules change, and pages are dated for that reason

Rules of evidence and procedure are amended on a regular cycle, and the pages here state the effective dates of the versions they describe. Federal Rule of Evidence 702 was amended effective 1 December 2023; Federal Rule of Evidence 107 took effect on 1 December 2024; the expert provisions of Federal Rule of Civil Procedure 26 are as amended effective 1 December 2010.

Material published before an amendment does not automatically become wrong, but it does become material about an earlier version. Anything relied on for a live matter should be checked against the current text of the rule and the current state of the case law.

Case descriptions are summaries

Decisions described here are summarized, with the citation given so that the opinion can be read. A summary is not the opinion, holdings are not always cleanly separable from dicta, and an appellate disposition can turn on procedural posture in ways that a summary compresses.

Several frequently cited decisions in this field are commonly mis-described in secondary writing, and where a page says so it is making an editorial judgment about the weight of authority. That judgment is offered with the citation attached precisely so that a reader can disagree with it after reading the source.

Third-party figures are not benchmarks

Where the site reports figures about fees or market practice, they come from surveys and reports published by companies that sell into the expert witness market, and each is identified with its publisher, date, sample and method. None is a probability sample, and most report what respondents say they charge rather than what was billed or collected.

Those figures are useful as an order of magnitude and as a description of structure. They are not a benchmark against which any individual quotation can be judged, and nothing on this site states what Hartzer Consulting charges.

No prediction, endorsement or guarantee

Nothing here predicts the outcome of any motion, hearing or trial, and nothing here should be read as an assurance that a particular course will succeed. Rules impose requirements, courts exercise discretion, and appellate review of these questions is generally for abuse of that discretion.

Nothing here endorses any expert, directory, referral service, broker, vendor, publication or software. Where such businesses are described, they are described structurally — how each is paid, and what that implies about the information it produces — without ranking or recommendation.

External material

Links are provided to primary sources so that statements here can be checked. Those destinations are controlled by others; their availability, accuracy and continued existence are outside this publisher’s control, and a link is not an endorsement of anything on the destination beyond the material cited.

Errors, broken citations and out-of-date statements can be reported through the contact page, and corrections are checked against primary sources rather than against other summaries.