How Elevator & Escalator Expert Witnesses Get Excluded Under Daubert — and How to Survive the Cross

Daubert is not a medicine problem. Under Kumho Tire and the 2023 amendment to Federal Rule of Evidence 702, the trial court's gatekeeping applies to every form of specialized testimony — elevator & escalator included. A 20-year study of 2,842 challenges to non-medical experts found that roughly half of those opinions were excluded or partially excluded, and the single most-cited reason was “unreliable methodology.”

The exclusion rarely happens in a written motion alone. It is built, piece by piece, in the deposition cross-examination — where opposing counsel walks a elevator & escalator expert into conceding scope, methodology, or an assumption that unravels the whole opinion. Here are the three traps, and how a prepared expert answers each one.

The three ways elevator & escalator experts lose ground

Scope: testifying outside your lane

The cross-examiner's question sounds simple:

You opine the elevator was unsafe — but you've never held an elevator mechanic's license, have you?

Why it works: The license/scope attack. Anchor to ASME A17.1.

A stronger answer: “I analyze the equipment against ASME A17.1 and accepted maintenance standards, which I'm qualified to apply, and I cited the specific code sections.”

Methodology: the reliability attack

The cross-examiner's question sounds simple:

Your opinion relied on the maintenance logs — you didn't inspect the unit yourself, did you?

Why it works: Methodology / records basis.

A stronger answer: “Where I couldn't inspect, I analyzed the documented maintenance and inspection records against the code and noted that limit.”

Assumptions: the one premise that sinks the opinion

The cross-examiner's question sounds simple:

You assume the safety device failed before the incident — but the last inspection passed, correct?

Why it works: The prior-failure assumption. Tie to inspection records.

A stronger answer: “I addressed the inspection history and the physical evidence and bounded my opinion to what they support rather than assuming a prior failure.”

How to prepare for the cross before you're sworn in

Every one of those traps is defeatable — but not by reading your report one more time. The experts who survive the cross have done three things:

• Rehearsed the cross-examination out loud, repeatedly, against a realistic examiner — so the scope concession, the methodology defense, and the assumption hedge are second nature.
• Mastered the record, so that when counsel asks them to recall the one line buried in thousands of pages of the maintenance logs, inspection reports, and code records, they can produce it in seconds rather than fumble.
• Stress-tested the report against FRE 702 — finding the reliability gaps before opposing counsel does.

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