Sequencing two experts to make a causation opinion land first

The situation

Kittipong's plan, before any of this started, was ordinary: keep working, keep saving toward a down payment with his partner Pensri, a bookkeeper, and let a shoulder injury from a fall at the retail warehouse where he worked heal on its own timeline. He had filed a claim against Tamar, the property manager responsible for the loading dock where he fell, on the basis that a known drainage problem had left ice on the ramp for days before anyone salted it. Because a workplace injury claim against another employer's worker can be barred outright under the Workplace Safety and Insurance Act when that other employer is also covered by the Act's Schedule 1 insurance fund, the claim could proceed in court at all only because Tamar's employer, a small independent property management company, was not a Schedule 1 employer - a status confirmed early on, before any of the work described here began. The claim was modest by litigation standards, but it mattered to a household budgeting carefully toward a home, and Kittipong had assumed, reasonably, that a documented fall on an icy ramp was the straightforward part of the case.

The file had been started by another lawyer, who retained an orthopedic specialist early on to assess the extent of Kittipong's shoulder injury and its expected recovery. That report was thorough on the injury itself but light on the question that actually decided the case: whether the fall, and therefore the property manager's alleged negligence, was the actual cause of the ongoing shoulder problem, as opposed to a pre-existing condition Kittipong had mentioned in passing to a physiotherapist two years earlier. Nobody had flagged that note as significant at the time; it had simply been part of Kittipong's medical history, disclosed honestly because he had nothing to hide.

When the file transferred to us partway through, after the original lawyer left private practice, the deadline for exchanging expert reports was close, and the existing report did not, on its own, answer the causation question the other side was already signalling they would attack. Tamar's lawyer had specifically flagged the physiotherapy note in a settlement discussion, making clear that if causation was not nailed down, they would argue Kittipong's shoulder problem predated the fall entirely and owed nothing to the loading dock. That argument, if it landed, would not just reduce the claim - it threatened to eliminate it.

We inherited a file with one expert report that answered the wrong first question, a deadline that did not leave much room to fix it, and a client whose confidence in the case had been shaken by hearing, for the first time, that his own medical history might be used against him. Kittipong needed to know whether the claim was still worth pursuing at all, or whether the gap in the file meant the case had effectively already been lost before he ever knew there was a problem.

Why this was harder than it looked

In a personal injury claim, causation and damages are two separate questions that have to be proven in the right logical order, even though it is common for lawyers to retain the damages expert first because the injury itself is usually the more visible problem. Damages evidence describes how badly someone is hurt and what that costs them. Causation evidence establishes that the specific incident being sued over is actually what caused the injury, as opposed to something else in the person's history. A damages report, however strong, means little if the other side can credibly argue the injury came from somewhere else, because a judge who accepts that argument never needs to reach the damages figure at all.

The orthopedic report already on file was a damages report in substance. It described Kittipong's shoulder limitations, his prognosis, and the impact on his work capacity in useful detail, but it treated causation as a given rather than something independently established, because the original retainer letter had never specifically asked the expert to address the physiotherapy note or rule out a pre-existing condition. That gap was invisible until the other side pointed directly at it, and by the time it surfaced, months of the litigation timeline had already passed.

Fixing this after the fact was complicated by timing. We could not simply discard the existing report and start over, because the deadline for serving expert reports was close and Kittipong's litigation budget, already stretched, could not absorb the cost of two full reports commissioned from scratch in sequence without risking a missed deadline. We needed a second expert - someone qualified to review the physiotherapy history and the fall itself and render an opinion specifically on causation - but that opinion needed to be filed in a way that supported, rather than duplicated or contradicted, the damages report already in hand, and it needed to happen fast enough that the second retainer did not itself become a new source of delay.

There was also a credibility risk in bringing in a second expert late. Opposing counsel could portray it as evidence the file was in disarray, or worse, as an attempt to manufacture an opinion after the original expert had left something unaddressed. We had to manage both the substance of the causation gap and the appearance of the fix, without ever suggesting to the Court that the first report had been wrong, only that it had answered a narrower question than the one now in dispute. That framing mattered because undermining the first expert's credibility would have weakened the damages opinion we still needed to rely on.

What we did

1. Reviewed the existing orthopedic report against the original retainer letter to confirm precisely what the expert had and had not been asked to address, which showed the causation gap was a scoping problem rather than an error in the report itself. This distinction mattered because it meant we could supplement the file without undermining work already done and already paid for.
2. Retained a second expert specifically on causation, a specialist qualified to assess the mechanism of the fall against the physiotherapy history and render an opinion on whether the pre-existing note described a separate, resolved issue or a condition genuinely aggravated by the workplace fall. We were deliberate about framing the retainer question narrowly so the new report would not simply duplicate the existing damages opinion.
3. Requested a short extension from opposing counsel for the causation report specifically, explaining candidly that the file had changed hands and that a focused causation opinion was being prepared, rather than trying to quietly slip a late report in without notice. Extensions requested this way are far more likely to be granted without a fight than ones that come as a surprise close to a deadline.
4. Sequenced service of the two reports so the causation opinion was filed first, establishing the link between the fall and the shoulder injury before the damages report's figures were ever put in front of the other side, so the damages numbers would be read against an already-established causal foundation rather than a disputed one. This meant opposing counsel had to respond to causation on its own terms first, rather than attacking damages and using that fight to cast doubt backward onto causation. Their response focused almost entirely on causation, exactly where we wanted the argument to happen.
5. Prepared Kittipong for a follow-up interview with the causation expert, since the physiotherapy note needed context only Kittipong could provide - specifically, what that earlier issue had actually involved and how it differed from the current shoulder problem. His own account, given directly and consistently, strengthened the expert's opinion considerably, and it was the first time since the file transferred that Kittipong felt he had a real role in shaping the outcome rather than simply waiting to hear what would happen next.
6. Obtained the physiotherapy clinic's full records rather than relying on the single note the other side had flagged, which showed the earlier issue had fully resolved eighteen months before the fall with no further treatment sought, undercutting the suggestion that it was an ongoing, unresolved condition. The clinic's discharge summary in particular closed the file on a healed, unrelated strain, which gave the causation expert something concrete to point to beyond Kittipong's own account.
7. Opened a settlement conversation once both reports were exchanged, presenting the causation and damages opinions together as a coherent package rather than waiting for a scheduled mediation, since the strength of the sequencing was most persuasive while it was fresh and unrebutted, and waiting for a formally scheduled mediation date would have given the other side more time to build a response to the causation opinion before either side sat down to talk.

The outcome

Tamar's side did not abandon its causation argument entirely, but the strength of the full physiotherapy record and the dedicated causation opinion narrowed what they were willing to fight over. Rather than proceeding to trial on a contested causation question, both sides negotiated a compromise settlement that fell below what Kittipong had originally hoped to recover but reflected a realistic assessment of the risk on both sides. Tamar's lawyer continued to argue, right up to the settlement, that the shoulder problem was at least partly attributable to the earlier issue, and the final number reflected a shared discount for that residual uncertainty rather than a clean concession on either side.

Kittipong received a settlement of roughly 22,000 dollars, within the range the claim had always realistically supported once the pre-existing condition argument was accounted for as a genuine, if ultimately unsuccessful, line of attack. It was not the full amount the original damages report alone might have suggested was available, and Kittipong was candid that he had hoped for more before understanding how much the causation question would end up shaping the negotiation. The gap between the two figures was, in effect, the price of the risk the file had inherited before we ever saw it.

What the case did avoid was a trial where causation was decided by a judge based on an incomplete record, which carried real downside risk given how firmly Tamar had signalled the pre-existing condition would be argued, and how the physiotherapy note had been flagged early. A loss on causation at trial would have meant no recovery at all, not a reduced one, so the negotiated figure represented a deliberate trade of upside for certainty. The sequencing of the two reports, and the extra work retrieving the full clinic history, meant the settlement was reached on the strength of a coherent evidentiary record rather than a rushed patch job, and Kittipong left the file with a clear understanding of why the number landed where it did rather than a sense that something had been left on the table unexplained.

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