On June 13 and 14, 2024, Paul participated in the Ontario Bar Association’s continuing professional development program “Anatomy of a Trial: Telling Your Trial Story,” held at the OBA Conference Centre on Toronto Street. The two-day program was a live demonstration of a civil trial from end to end, structured around a motor vehicle personal injury action. Superior Court judges presided over each segment. Senior advocates demonstrated the work, and equally senior counsel delivered the debrief commentary that followed each demonstration. The keynote address on the second day was delivered by Marie Henein.
Paul’s demonstration was on the morning of Day 2: the cross-examination of the defence accident reconstruction engineer. His partner at Davidson Cahill Morrison LLP, Jim Davidson, demonstrated the defendant’s opening statement on Day 1. The two segments addressed different sides of the same case and different stages of the trial, but they shared the same underlying discipline: structuring the work to advance the client’s story while testing the other side’s.
The format
The OBA’s Anatomy of a Trial programs are a distinctive piece of Canadian trial advocacy education. Each segment of the program consists of a live demonstration by an experienced advocate, performed in front of a presiding Superior Court judge, followed by a structured debrief by a separate senior counsel on what worked, what did not, and what the demonstration illustrates about good trial practice. The combination of live demonstration with critical commentary is closer to a teaching trial than to a conference panel, and it produces a depth of practical instruction that conventional CPD programming cannot match.
The 2024 program covered the full sequence of a civil trial: document briefs, the trial management conference, pre-trial motions on Pierringer agreements and accident benefits settlements, opening statements, the examination and cross-examination of the settled defendant, of independent witnesses, of the plaintiff, of accident reconstruction and biomechanical experts on both sides, a voir dire on the admissibility of expert opinion, the defendant’s own evidence, and closing argument. Each piece of the architecture was demonstrated and debriefed in turn.
The defence expert segment
The defence in the mock trial called an accident reconstruction engineer. Paul cross-examined that witness. The debrief identified two themes for that segment: the expert witness as a teacher, and the advancement of the cross-examining party’s case theory through the cross of the opposing expert.
Those themes carry across the full range of civil trial work. The defence expert in a personal injury action is structurally similar to the defence expert in a medical malpractice action. The disciplines that get the cross-examination right are the same.
The expert as teacher
An opposing expert who walks into the courtroom is generally trying to do two things at once. The expert is delivering an opinion that supports the defence theory, and the expert is also explaining the technical material the trier of fact needs to understand to evaluate that opinion. Both of those roles create opportunities for the cross-examiner.
The first opportunity is in the teaching itself. Where the expert has explained the methodology in plain terms, the cross-examiner can use that same plain-language explanation to set up the questions that follow. The expert who has explained how an accident reconstruction is performed, or how a clinical diagnosis is made, has supplied the cross-examiner with the conceptual vocabulary the rest of the cross will use. The trier of fact will be familiar with the framework by the time the cross begins.
The second opportunity is in the inevitable simplification. An expert who teaches well simplifies. The simplification creates seams: assumptions the expert had to make, complications the expert chose not to discuss, alternative methodologies the expert decided not to follow. Each of those seams is a question the cross-examiner can put, in the expert’s own framework, in front of the trier of fact who is now equipped to follow it.
Foundation evidence
A second pillar of effective cross-examination of an opposing expert is foundation evidence. Every expert opinion rests on a foundation: the facts the expert was given, the data the expert relied on, the literature the expert took as authoritative, the methodology the expert applied. The foundation is the part of the opinion that is most vulnerable to cross, because it can be tested without requiring the cross-examiner to debate the expert on the expert’s own ground.
The defence reconstruction engineer in a motor vehicle case relies on physical evidence (scene photography, vehicle damage, scuff marks, video where available), on documentary evidence (police reports, witness statements), and on assumptions (speeds, sight lines, reaction times). Each input is a foundation question the cross-examiner can develop. The defence medical expert in a medical malpractice case relies on the chart, on the literature, on the clinical history, and on the assumptions the expert was asked to make. The structure is the same.
Cross-examining on the foundation does not require challenging the expert’s qualifications, although the qualifications are part of the picture. It requires a careful, often time-consuming working-through of how the opinion was built. Where the foundation does not bear the weight the opinion places on it, the trier of fact will see the gap.
Advancing your case theory
The third pillar is the use of the cross to advance the cross-examiner’s own theory. The defence expert is on the stand to support the defence theory. The plaintiff’s cross-examiner is using the defence’s witness to put plaintiff-side propositions in front of the trier of fact, in the expert’s own voice, with the expert’s own qualifications and authority attached.
This is the harder discipline. It requires the cross-examiner to have identified the plaintiff propositions the defence expert will accept (or cannot credibly refuse), the literature the defence expert will recognize, the clinical guidelines the defence expert applies in their own practice, and the assumptions the defence expert can be drawn into making. Each of those becomes an opportunity for the cross to do something more than damage the defence opinion; the cross becomes part of building the plaintiff’s case.
In medical malpractice practice, the equivalent is the cross of the defence physician on the relevant practice guidelines, on the patient population data, on the clinical literature, and on the standards the defence physician himself or herself applies when treating other patients. The same logic that animates the cross of the defence engineer in a motor vehicle case animates the cross of the defence physician in a medical malpractice case. The witness is different; the discipline is the same.
Why this segment of trial work matters
Cross-examination of opposing experts is the segment of trial work where preparation pays the highest dividends. The witnesses are sophisticated. The material is technical. The trier of fact is often relying heavily on what the experts say. And the time available, once trial begins, is unforgiving.
The work that produces a good cross of an opposing expert is done in the months before trial: the careful read of the expert’s report, the parallel read of the literature the expert relies on, the conversations with the plaintiff’s own experts about what the defence expert is likely to say and not say, the working draft of the cross with each question paired to its evidentiary source, the simulated cross delivered to colleagues who will press back on the weaknesses. The cross itself, at trial, is the product of that preparation, not the place where the work happens.
Closing observations
The OBA’s Anatomy of a Trial programs are valuable for the same reason teaching trials have always been valuable. The components of good trial practice are not mysterious, but they are difficult to acquire from anywhere except the courtroom itself, and the courtroom is an expensive classroom. The OBA’s program brings the courtroom to the program, in a setting where the demonstrations can be paused, examined, and built upon.
Paul was glad to participate, and grateful to the program chairs (Brian Bangay, Lindsay Charles, Troy Lehman, and Katherine Di Tomaso) and to the OBA for the opportunity to contribute. Cross-examination of opposing experts is a topic the medical malpractice bar has reason to think carefully about. The principles travel.
