If you’ve been seriously injured because another person was negligent – in a traffic collision or in any other scenario – your successful pursuit of a personal injury lawsuit may hinge on your ability to explain clearly the facts and issues involved in the case.


In fact, expert witnesses can be helpful to your car accident law firm during both the preparation and the presentation of a personal injury case. During the out-of-court negotiations that precede a trial, experts who explain the facts can help the opposing parties arrive at mutually acceptable settlements.

When a personal injury case can’t be settled out of court and goes to trial, expert witnesses can provide the details, insights, and background information that may not be common knowledge to judges, juries, attorneys, plaintiffs, and defendants.

Personal injury lawyers regularly work with professionals who may testify as experts in personal injury cases: accident reconstruction experts, toxicologists, civil engineers, ballistics experts, medical examiners, and other experts who may be called to testify at a trial or a deposition.


Personal injury case witnesses are either “lay” witnesses or “expert” witnesses. Although a lay witness can be defined as any witness who’s not an expert, what makes someone an “expert” is more difficult to define.

In fact, there’s no single definition for what makes a witness an expert, but education, experience, special training, and special knowledge or research are generally accepted indications of expertise in a particular field of knowledge.

The specific factors that may define a witness as an expert witness include:

1. academic credentials including degrees and awards
2. publication in peer-reviewed journals
3. educational and professional experience
4. previous expert witness recognition and experience
5. public and/or professional reputation


Generally speaking, lay witnesses have some direct personal connection to a case, and the kind of testimony lay witnesses can offer is generally limited to their direct personal knowledge.

A lay witness may be an eyewitness, a police officer who filed an accident report, or a doctor who treated the victim. Victims and defendants themselves may also be lay witnesses.

Experts, however, are specialists who may have no personal connection to a case, but their training and expertise can provide insights and explanations regarding the more complicated or technical aspects of the case.


If you are injured by another person’s negligence, which experts will you need to testify on your behalf? Obviously, it depends on the nature of your case. An injury case that arises from a building collapse, for instance, may require the testimony of an architect or an engineer.

In a medical malpractice case, you may need testimony from a recognized medical authority. If you’re injured because your brakes or tires were defective, you may need a certified mechanic or an automotive engineer. Your personal injury lawyer will find the expert you need.


While the testimony of lay witnesses must be based on their direct personal knowledge, expert witnesses are granted more latitude. The opinions they offer are presumed to be impartial and based on their specialized knowledge.

Expert testimony can be enlightening, persuasive, and powerful. It can make the difference. In a personal injury trial, expert witnesses are allowed to offer opinions in these circumstances:

1. The expert’s specialized knowledge will help the judge or jurors understand the evidence.

2. The expert’s opinion is based on research and facts.

3. The methods used to arrive at the expert opinion are trustworthy and proven.

4. Those methods were properly applied to the evidence in this particular case.


If you testify in your own personal injury trial, you obviously have a vested interest in the outcome of the case. If your family or friends testify, their testimony may also be considered biased.

Judges and juries have reservations about potentially biased testimony, but expert witnesses have no personal stake in a case’s outcome, so their testimony is usually considered more objective and reliable.

Expert witnesses help judges and juries work through evidence that can be complex and difficult. To take just one example, a toxicology report requires a full explanation from someone who understands the toxicology screening process and the way that toxicology results are analyzed.

If you are injured by negligence and your case becomes a personal injury trial, winning may depend on how much detail you can provide and on how well that detail is explained.

Your expert witness can help clear up any confusion and will try to emphasize the evidence and facts that are most helpful to your case.


Not every personal injury case will require expert testimony. For example, if a drunk driver’s negligence severely injures you, a breathalyzer result and a statement from your own doctor may be all of the evidence that you need.

If you’ve been injured by someone’s negligence, an expert can provide insights and convincing testimony on your behalf, but most expert witnesses expect to be paid well for their time and expertise.

Every case, of course, is different, so you’ll want to discuss with your personal injury lawyer whether you need an expert’s testimony. Everything depends on the details of your case – and how easy or hard it will be for others to understand those details.


If you’ve been injured by someone else’s negligence in Massachusetts, you are entitled by law to full compensation for your medical costs, lost wages, and more, but to win that compensation, you’ll need to be advised and represented by an experienced Boston personal injury attorney.

It costs nothing to learn more about your legal rights and options. If you’re injured, you’re entitled to a free consultation with an attorney who will review your case and explain where you stand legally.

If your attorney recommends legal action, you’ll pay no legal fees until your attorney recovers a settlement or a verdict on your behalf.

Get the legal help you need, speak to an accident attorney at once if you’ve been injured, and understand that if you are a victim of negligence in Massachusetts, you have rights, and the law is on your side.