My question is, how do people get to be expert witnesses in court cases? The other day I was reading an excerpt from a trial transcript, published in a trade journal, where a so-called expert was describing how a certain car feature is supposed to work, and it occurred to me that I could do a far better job of explaining it than he did. But how are expert witnesses chosen? And who decides who is an expert? — Curious in Cleveland

Dear C.C.: Interesting question. Thanks to television dramas like Law & Order, most people think of expert witnesses as psychiatrists who testify about a defendant’s sanity, or forensics specialists asked to identify somebody’s DNA. But in real life, the court system needs expert witnesses in any field you can think of, and some you probably never would. (More about that in a minute.)

Much of what expert witnesses do is behind the scenes, as consultants to lawyers who want to understand the technical details of their cases, some of which are settled without ever going to court at all. In several states, attorneys are required by law to confer with an expert to make sure their would-be plaintiff client has a credible complaint before they even file a lawsuit.

So there’s plenty of demand for expert witnesses and, as U.S. society gets more and more litigious, a mini-industry has sprung up to connect people who know a lot about something with the lawyers who need them to expound on it. Google “expert witness referral companies” and you’ll find about a dozen operating nationwide.

Take, for instance, Denver-based Expert Consulting Services, which maintains a database of over 1,000 experts in a wide variety of fields. ECS president Ingrid Vinci was a practicing medical-malpractice attorney in 2006 when she started the firm because she and her colleagues were constantly searching for expert witnesses. “Lawyers didn’t want to spend endless hours tracking down experts, and people with expertise had no reliable way of knowing who needed them,” she says. Today, according to Vinci, referral companies like ECS streamline the process.

Later on, if you establish a strong reputation as a seasoned witness, you might be able to hang out your own shingle and have lawyers contact you directly. But for now, the best way to get started is to sign up with a referral service, or more than one.

Here’s how it works at ECS (and, with slight variations, at most other referral services): You submit your bona fides, including a detailed resume and contact information. Then, when the service gets a request from a lawyer for someone with your expertise, the service gets in touch with you and describes the gig, usually with a brief summation of the facts of the case and an estimate of how much time you’d have to put in.

“You’re never obligated to take a case,” says Vinci. “If it doesn’t interest you, or it doesn’t fit your schedule, no problem. We’ll try you next time.”

That kind of control over your own hours could be a plus for you in a second career, but people often act as expert witnesses as a sideline while they’re still working full-time, too. “Some experts work more or less continually, like one of our orthopedists who testifies about soft-tissue injuries three or four times a month,” says Vinci. “How steadily you work depends, in large part, on how much demand there is for your area of expertise.” The more referral services you sign on with, she adds, the busier you’re likely to be.

Once you accept an assignment, the attorney who’s hiring you pays your fee, out of which a “small percentage” goes to the referral service, Vinci says. “Expert witnesses set their own rates, ranging from “$150 an hour for an auto mechanic to $1,500 an hour for a neurosurgeon.”

How do you decide what your expertise is worth? ECS can give you a range of fees charged by others in your field, so you can set your price accordingly—maybe starting out near the lower end of the range, and charging more as you gain experience. “There is no upper limit,” says Vinci. The only caveat: “If you set a very high fee,” she adds, “be ready to justify why your time is worth the money.”

Some expert witnesses command a premium because of their esoteric knowledge. In one case a few years ago, Vinci recalls, a man was suing a pet shop. He had paid thousands of dollars for koi fish and claimed that, when they were added to the pond that contained his other koi, all the fish went belly-up (literally). So his lawyer asked ECS to find him a veterinarian who specialized, not just in exotic pets, but in fish diseases.

“It turns out that koi can carry a particular strain of the herpes virus that is highly contagious, and fatal to other koi fish.Who knew?,” says Vinci. So she hunted down a veterinarian who explained that to a jury. “We still work with him today,” she says.

Given that lawsuits over auto safety are so much more common these days than courtroom disputes about dead fish, you should be able to find work as an expert with relative ease. Good luck!

Talkback: Have you ever served as an expert witness in a court case? If so, would you recommend it as a second career? Leave a comment below.