Expert selection gets discussed as a credentials question. Which specialty, which publication record, which institution. Firms running a bellwether program hit a second question underneath that one, usually later than they would like: whether the person can give the same opinion, the same way, for years, while the docket keeps growing around them.
Josh Hyatt is President of Expert Institute, which provides expert witness sourcing and data to law firms. I asked him seven questions in writing about the firm’s side of that work. What he adds is that the things that sink an expert at a Daubert hearing are on the record before retention: a deposition in another case where the witness said the opposite, or a testimony history sitting almost entirely on one side of the docket. Pulling that record across a full career is tedious enough that most firms skip it, and opposing counsel is counting on that. He also answered a question most vendors would step around: whether there is a point where he tells a firm that the expert it wants does not exist. There is.
On starting at intake
Meldofsky: How early does expert review need to start in a mass tort, and what does a firm give up by starting late?
Hyatt: At intake, not when a trial date lands on the bellwether pool. Here’s the mistake I see most: firms vet experts the way they’d vet one for a single-plaintiff case, when a mass tort expert is a completely different asset. You’re not looking for someone who’s right for one set of facts. You’re looking for someone who can hold the same opinion, under cross, across dozens of depositions, over years, and still has the bandwidth to keep doing it as the docket grows.
That’s a much smaller pool than “qualified experts in this specialty,” and firms that start late don’t find that out until they’re already committed to someone who can’t sustain the pace.
On what a bellwether expert has to survive
Meldofsky: What is different about sourcing experts for a bellwether program with thousands of claimants versus a single-plaintiff case?
Hyatt: Capacity and durability, not credentials. A single-plaintiff expert has to be right once. A bellwether expert has to be right the same way, repeatedly, for years, while the docket keeps adding plaintiffs with slightly different facts.
I’ve seen firms retain someone who was clearly the strongest CV in the room for one case, then discover two years in that the person doesn’t have the time, the testimony discipline, or honestly the appetite to do it forty more times. That’s not a qualification problem. It’s a capacity problem, and it should be underwritten at retention, not discovered at deposition six.
On what the budget leaves out
Meldofsky: What does expert work actually cost across a bellwether program, and which line item do firms consistently underestimate?
Hyatt: I won’t put a number on it publicly. It moves too much by jurisdiction and specialty to be honest as a headline figure.
But structurally: retention and initial review, report development, deposition and trial prep, those get budgeted. What doesn’t is ongoing file maintenance for the life of the case. Keeping the expert current as new plaintiffs join the docket, and re-briefing them every time the science, the guidance, or the opposing expert record shifts. Over a multi-year program that cost compounds, and it’s the one firms consistently leave out of the plan.
On what actually shows up in a Daubert challenge
Meldofsky: Where do plaintiff firms get exposed on expert qualification? What shows up in a Daubert challenge that a better front-end process would have caught?
Hyatt: Testimony history, not credentials. The CV almost never sinks an expert. What sinks them is a prior deposition transcript, in a different case, where they said something that contradicts the opinion they’re giving you now. Or a pattern showing nearly all their case history sits on one side of the docket.
Both are findable before retention if someone actually pulls the transcript record instead of just the publication list. That’s the front-end process most firms skip, because it’s tedious to do by hand across a full career. It’s the gap Expert Institute’s vetting was built to close, keeping that record current on an expert for the life of the case rather than only at intake.
On theories the literature doesn’t support
Meldofsky: A firm comes to you with a causation theory the published literature does not yet support. What does that conversation look like on your end, and is there a point where you tell a firm the expert they are describing does not exist?
Hyatt: Yes, that point exists, and I’ll say it plainly.
I ask what published or peer-reviewed basis exists, even indirectly, for the mechanism the firm believes. If the literature is silent rather than just thin, the conversation shifts to what would need to be true for a qualified expert to defensibly get there. An interim step, an analogous exposure pathway, a framing the literature does support, instead of finding someone willing to originate a novel theory on the stand.
If a firm wants the theory more than the literature supports it, my job isn’t to go find someone who’ll say it. It’s to tell the firm that.
On a record that keeps moving
Meldofsky: How do you find out whether an expert has published a position that cuts against your theory, or has worked the other side of a similar case?
Hyatt: Two checks, run on the individual, not the specialty. Everything they’ve published under their own name that touches this causation question or something close to it, going back through their full career, because a paper from a decade ago is exactly what shows up in cross-examination. And separately, which side they’ve testified for historically, in this docket and adjacent ones.
Done manually, that’s someone on staff working through public filings, journals, and transcript databases case by case, and it goes stale the moment you stop looking. That’s the problem Expert Institute’s Radar was built to solve. It runs that check continuously against an expert’s public record for the life of the retention, so a paper they publish or a deposition they give in an unrelated case eighteen months into your litigation doesn’t surface for the first time when opposing counsel finds it.
On the acetaminophen reversal
Meldofsky: The Second Circuit vacated the exclusions in the acetaminophen MDL in July and sent it back with the general causation experts reinstated, while stating the panel was deciding admissibility rather than causation. From where you sit, what changes for a firm when an appellate court moves the admissibility line in the middle of a litigation?
Hyatt: It’s a good real-time example of something firms underprepare for. The admissibility bar isn’t fixed once a district court rules on it. It can move mid-litigation, and when it does, it retroactively changes which of your earlier expert decisions were actually sound.
Practically: don’t treat a trial-court exclusion as final while it’s on appeal. Keep that expert’s file current instead of walking away, because reversal can put them back in play years later. A line movement at the appellate level applies across the whole docket, not just the case that got appealed, so every expert vetted or dropped under the old standard is worth a second look.
And the panel’s own framing, admissibility rather than causation, cuts both ways. A firm that reads reinstatement as validation of the underlying science is making the same category error, in reverse, that got those experts excluded the first time. It’s why we treat vetting as something that runs for the life of the case instead of a box checked at retention.
On July 13, 2026, the Second Circuit vacated Judge Denise Cote’s exclusion of the plaintiffs’ general causation experts in the acetaminophen autism MDL and remanded, reviving several hundred dismissed cases. The panel framed its decision as one about admissibility under Rule 702 rather than about whether acetaminophen causes autism. — DM
Josh Hyatt is President of Expert Institute, which provides expert witness sourcing and data to law firms.
Hyatt’s answers appear as written, edited for length and clarity, with promotional phrasing trimmed in three places. — DM
Disclosure: Lawsuit Informer and Lawsuit Center, both founded by the author, publish consumer-facing pages on the acetaminophen autism litigation discussed in the final question. No payment was exchanged in either direction for this interview.