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See the 60-second demo →In April 2024, the Maryland Appellate Court affirmed summary judgment in a brachial-plexus / shoulder-dystocia case. Both plaintiff experts had been excluded. The reason was on the deposition transcripts.
At deposition, both experts categorically excluded maternal forces as a possible cause of the brachial-plexus injury. By the time the Daubert hearing rolled around, the defense had pointed to peer-reviewed literature establishing that maternal forces can cause this kind of injury. Both experts pivoted. They conceded that maternal forces could cause the injury in principle — but said they had ruled them out in this specific case.
The trial court treated the mid-stream pivot as evidence that the methodology was result-driven rather than reliably applied. The Appellate Court affirmed.
If you are a plaintiff attorney whose case includes any contested causation question — and most cases do — the Maryland brachial-plexus decision is the cleanest illustration of why deposition prep is the most important Daubert prep work you can do.
The plaintiffs alleged that the defendant's negligence during delivery — specifically, the application of physician forces during a shoulder-dystocia maneuver — caused the child's brachial-plexus injury. Two experts, both obstetricians, were retained to opine on causation. Both filed reports concluding that physician-applied forces were the cause.
At deposition, both experts went further. Asked whether maternal forces (the natural propulsive forces of labor) could cause this kind of injury, both said no. The exclusion was categorical.
The defense was ready. By the Daubert hearing, the defense had compiled the relevant peer-reviewed literature, which holds that maternal forces can in fact cause brachial-plexus injury. Both experts, confronted with the literature, pivoted. They now conceded the general proposition. They distinguished it on this case's facts — saying they had ruled out maternal forces here specifically.
The trial court excluded both experts. Three findings drove the result:
The Maryland Appellate Court affirmed. The case ended.
Inconsistencies between an expert's deposition transcript and the same expert's later testimony are the single most common 702 trap in 2026 motion practice. The Acetaminophen MDL contained a related dynamic — experts whose Bradford Hill weighting could not be replicated under examination. The Engilis Ninth Circuit decision in 2025 contained another version — the expert who could not say at deposition whether the plaintiff was obese, then offered a differential etiology that depended on ruling out obesity. The pattern is the same across cases. Methodology that does not survive its own deposition does not survive Daubert.
There are two reasons this pattern is so prevalent. The first is that experts who are deeply committed to a clinical view of the case sometimes overstate that view at deposition. The "categorical exclusion" answer — "no, that cannot happen" — feels stronger to the expert than the more accurate "yes, in principle that can happen, but I have ruled it out here." The first version is the version that ends up in the transcript. The second version is the one that would have survived Daubert.
The second reason is preparation asymmetry. The defense knows what the literature says about every alternative cause for every common injury type. They will surface the literature at the Daubert hearing if it is not surfaced earlier. The plaintiff-side expert who has not been prepped on the literature is, by default, the expert who will pivot when confronted with it. That pivot is the Daubert exhibit.
A related case worth noting in this same vein: the 2025 NJ MILD spinal-procedure decision. There, the expert had said in deposition that he would defer to a neurologist on the cause of the patient's leg pain — twice. Then his report opined on it directly. Different mechanism, identical structural problem: the deposition transcript and the report told different stories, and the court treated the gap as a methodology defect.
Four concrete steps:
1. Run a literature audit on every alternative cause before the expert is deposed. For each alternative cause that the defense might raise — maternal forces in a shoulder-dystocia case, prematurity in a CP case, obesity in an oncology case, smoking in a lung case — pull the peer-reviewed literature and walk it through with the expert. The expert needs to know what the literature says, what the strongest defense citation is going to be, and how to answer in deposition without categorical statements that the literature itself contradicts.
2. Coach the expert against categorical exclusions when the literature does not support them. A plaintiff-side expert who says "no, that can never cause this" when peer-reviewed literature says otherwise has not pre-empted the issue — they have created it. The right answer at deposition is the more accurate one: "Yes, the literature recognizes [alternative] as a possible cause; in this specific case, I ruled it out for these reasons, which I documented in my report." That answer survives the Daubert hearing because the report supports it.
3. Build the rule-out documentation into the report before the deposition. The reason the Maryland brachial-plexus experts could not survive the pivot is that their reports had not done a documented rule-out of maternal forces. They had categorically excluded the possibility, which is not the same thing. A documented rule-out — "the literature recognizes maternal forces as a possible cause; in this case, the records show X, Y, and Z, which together rule it out for these reasons" — gives the expert a stable position in deposition and at the hearing.
4. Treat the deposition transcript as the report's truth set. The gatekeeping inquiry under FRE 702 is whether the methodology was reliably applied. The clearest evidence of how the expert applied the methodology is the deposition transcript. A report that the deposition cannot support is a report that does not survive Daubert. Audit the deposition prep with that priority in mind.
A broader point: depositions used to be discovery. After 2023, depositions are also Daubert artifacts. Every answer is a potential exhibit in a future motion. Plaintiff firms that have not adjusted their deposition prep accordingly are running uphill.
MedLegal AI's Daubert workup tool runs every Daubert challenge — anticipated or actual — against the expert's own past deposition record automatically, surfacing inconsistencies before the defense does. The tool's deposition-prep mode generates an "anticipated cross" memo for the expert that includes the most aggressive specialty-narrowing, qualifications-narrowing, and methodology-criticism lines a defense Daubert motion is likely to raise. For each anticipated line, the tool maps the relevant peer-reviewed literature and the expert's prior testimony, so the expert's deposition answers are pre-aligned with what the report and the literature actually support. The point is to prepare smarter for Daubert challenges — to make sure the deposition transcript and the report tell the same story before the defense reads them side by side. You can run a free Daubert workup on your expert here.
The Maryland brachial-plexus decision is the cleanest illustration in recent memory of why deposition prep is the centerpiece of a serious Daubert posture. Expert flip-flops at the Daubert hearing are the most reliable predictor of exclusion. The cure is procedural: pre-deposition literature audits, accurate rather than categorical answers, and report documentation that supports the expert under examination. The cases that survive Daubert in 2026 will be the ones whose deposition transcripts read like the gatekeeping order's preferred record.
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MedLegal AI is software, not a law firm. We do not provide legal advice. All AI-generated outputs require independent review by a licensed attorney.
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