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Expert Witnesses In MA Personal Injury Cases

The highway and roads on the North Shore and throughout Massachusetts get more crowded all the time. Rush hour seems to start before 6:00 am and not to end before 7:00 pm. The Route 128 and Route 1 interchange is crowded.  Where those highways intersect with Route 95: in Reading, Stoneham, Woburn, Lynnfield and Saugus, can be like a parking lot all day long. Congestion and high speed merges cause accidents ranging from fender benders to serious pileups.

When you have been in an accident and after the shock wears off and the medical situation is stable, it is important to speak with a Massachusetts injury attorney without delay and before you say anything to any insurance adjuster. Getting your attorney involved at an early stage will help your attorney put together the fact witnesses and evidence to prove your case and damages. Often this will include use of an expert witness.


An expert witness is someone with “scientific, technical, or other specialized knowledge” that will help the jury understand the facts of the case. The expert must be qualified by his or her  “knowledge, skill, experience, training or education.” Mass. Guide to Evidence, § 702; Commonwealth v. Lanigan, 419 Mass. 15 (1994). An expert differs from the typical, fact witness (often called a lay witness) because a lay witness may only testify to facts and experiences based on his or her own personal knowledge. A lay witness may not testify to facts that require scientific, technical or specialized knowledge. Mass. Guide to Evidence, § 701.

A recent Massachusetts Appeals Court decision highlights the importance of ensuring your expert witness is qualified to testify as an expert – it can make or break your case.

In Peterson v. Foley, 77 Mass. App. Ct. 348 (2010), both the plaintiff and defendant used a different expert witness who testified to the cause of the accident and who was at fault. The trial judge allowed the police officer that investigated the accident to testify as an “expert” for the defendant. The officer’s opinion was that the plaintiff, Peterson, was at fault because he was driving at an excessive speed and not paying attention. The jury believed the officer and the plaintiff did not recover for his injuries.

Peterson appealed. The Appeals Court ruled that the police officer was not an accident reconstruction expert and therefore not qualified to give expert opinion on the speed of the vehicle based on the accident’s aftermath.  Even though he had responded to hundreds of accidents, the Appellate Court concluded that the police officer didn’t have the necessary training, study, and expertise in the laws of physics to reconstruct an accident.  Accident reconstruction experts use mathematical formulae and physics in order to reconstruct the accident. Experts consider such facts as the length and type of skidmarks; the weight of the vehicle; and the strength and stiffness of the materials that make-up the vehicle.

The police officer, on the other hand, examined the vehicular impact with a tree and the distance the car spun away from the tree. He did not arrive at his conclusions from scientific formula. His opinions were based on his observations of the tree and vehicle; he did not arrive at his conclusion based on knowledge, skill, experience, training or education.  Therefore he was not qualified.

As we see, the outcome of an accident case may rest entirely on expert testimony.  Selecting a qualified and effective expert can be critical.

So, it is important to get an accident attorney involved as soon as possible to give you and your attorney the time to discover the facts; and if necessary, find an expert who has the training and specialized knowledge to give an opinion about the accident. A case can rise and fall on the strength of your expert witness.

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