Why Physicians Do Expert Witness Work (And What It Does to Their Medicine)

By John Mahoney · August 18, 2026

Ask physicians who serve as expert witnesses why they keep doing it, and the money is rarely the first thing they say. The first thing they say is that it made them better doctors — and they usually say it with some surprise.

That surprise is worth taking seriously, because it points at something the specialty-society CME catalog cannot sell you.

Here is what actually happens.

You start reading differently

In practice, you read to stay current. Abstract, conclusion, maybe a glance at the forest plot. Twenty minutes between patients, a journal club every few months, a conference session you half-watch while answering messages.

In a case, you read to defend.

You go to the methods section, because the methods section is where you will be attacked. You find the exclusion criteria. You check whether the endpoint was the one that matters or the one that reached significance. And at some point you notice that the study your position rests on enrolled forty-one patients, at three academic centers, none of whom looked much like the patient in this record.

That is an uncomfortable discovery. It is also the most useful kind of discovery there is.

Nobody has asked you to justify your clinical reasoning at that resolution since fellowship — and in fellowship you were defending someone else's ideas, badly, in a room full of people who already agreed with you. This is different. Someone is going to read what you wrote, hire a physician of equal standing to disagree with it, and then question you about the gap.

Then you go back to clinic on Monday and you are sharper. Not because you learned a new fact. Because you were forced to examine something you thought you already knew.

You get the last chapter

This is the part physicians underrate most.

In clinical practice you see a slice. The patient comes in, you make a decision under time pressure with partial information, and they leave. Maybe you get a follow-up note. Usually you get nothing. You will go your whole career without learning how most of your decisions turned out.

Medicine is practiced almost entirely without the last chapter.

An expert case hands you the whole book. Every note from every service. The nursing documentation nobody reads. The vitals at 3 AM and the page that followed. The consult that was requested and the consult that actually happened, which are sometimes different things. The handoff where a real concern got softened one word at a time across three shifts until it disappeared entirely. And then the outcome, which you can read against everything that preceded it.

You are reading the natural history of a decision. That used to be available only at morbidity and mortality conference — and M&M is compromised by exactly the things a case file is not: incomplete records, institutional politics, a room full of people who need to work together on Monday, and the powerful human urge to conclude that nothing could have been done differently.

Physicians come out of that experience changed in specific, observable ways. They document differently, because they have now seen what a thin note looks like to a stranger reading it two years later. They escalate differently. They stop assuming the next person read the chart.

There is no course that does this.

You have to say what you actually know

Ask a good clinician why they did what they did and you will often get some version of: It's what you do.

That is not evasion. It is expertise compressed into reflex. Thousands of repetitions collapse into an instinct that fires before you can narrate it, which is precisely what makes an experienced physician fast and safe.

Expert work makes you decompress it.

You have to state, in writing, what a reasonable physician in that specialty, in that setting, with that information available, at that hour, would have done. You have to separate what was reasonable from what was optimal — a distinction the entire field turns on and that most of us never say out loud, because in daily practice we are aiming at optimal and the gap doesn't come up.

You also have to mark the edge of your own knowledge, out loud, in a setting where a wrong guess is expensive. Most physicians have never located that edge precisely. It turns out to be closer in some places and much further out in others than you assumed.

Once you have taken the instinct apart, it does not fully reassemble. Physicians who do this work report that they teach better afterward, that their notes get clearer, that their differentials become explicit where they used to be intuitive. Residents notice first.

The honest ledger

None of this argues that the work is easy or that everyone should do it.

The obligations are real. You are not an advocate; you are a neutral opinion that one side happened to retain, and the moment you start rooting for an outcome you become both a worse expert and a more vulnerable witness. That means being willing to tell an attorney the case has no merit, after they have paid you to read it — and the physicians who last in this work are the ones who find that clarifying rather than awkward.

Everything you write is discoverable. Your prior testimony follows you. Your CV will be read more carefully by opposing counsel than by any hiring committee you have ever faced.

And it is genuinely demanding, unglamorous reading. Thousands of pages, much of it duplicative, some of it illegible.

But notice what the demands have in common: they are all demands for rigor about your own specialty. That is the whole argument. The work is hard in the direction you already chose to be good at.

The part about money, which is real but second

Physicians looking at a second income stream have all run the same math. Extra shifts pay well and cost you the thing you were trying to protect. The consulting gig, the side business, the passive-income seminar — they pay you to be somewhere other than your specialty, and to slowly become someone who used to practice medicine.

Expert work is structurally different. You are paid specifically to go further into the thing you already spent a decade mastering. The hours are largely yours to schedule. The rate reflects specialist expertise rather than shift coverage.

And the compounding runs in the right direction. Each case makes you incrementally better clinically and incrementally more credible as an expert, at the same time, from the same hours. Very few second incomes have that shape. Most ask you to choose.

Who this is actually for

The most common reason physicians never take a first case is a belief that they are not senior enough — that this work belongs to emeritus names and department chairs with three hundred publications.

What attorneys actually need is narrower and far more available. Someone in current practice, because anyone whose clinical work is behind them gets attacked for exactly that. Current board certification. Someone who does the specific thing at issue routinely rather than famously. And someone who can explain it clearly to twelve people who did not go to medical school.

That last one is the real filter, and it is not a seniority filter. It is the ability to be clear under pressure without being condescending — the same skill that makes a physician good at consenting a frightened patient at 11 PM.

If you can do that, you are closer to qualified than you think. And the first case will teach you more about your own specialty than the last three conferences you attended.