When many people think of witnesses in a court trial, they think of someone that saw the incident that is the basis of the trial (e.g., a person that saw a car accident or a slip and fall). Those are called fact or lay witnesses. However, at the trial, these witnesses are limited to testifying only about the things that they saw or heard firsthand.
Fact or lay witnesses are unable to testify about their opinion of how or why something happened. This can be difficult in complex lawsuits. Fortunately, there is another type of witness known as an “expert witness” that can testify about their opinion of how or why something happened.
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What is An Expert Witness?
Generally speaking, an expert witness is a person with specialized training, knowledge, experience, or education that allows them to help explain complex facts to the jury or court. The important difference between a fact witness and an expert witness is that an expert witness can provide their opinion on an issue, but a fact witness cannot. This is because the expert’s opinion is based on their specialized experiences and training.
Who Qualifies As An Expert Witness?
Pennsylvania law states that a witness may qualify as an expert witness based on their specialized training and experience, and testify about their opinion if:
- the expert’s scientific, technical, or other specialized knowledge is beyond that possessed by the average layperson;
- the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; and
- The expert’s methodology is generally accepted in the relevant field.
Additionally, Pennsylvania follows the standard for the admission of scientific evidence found in the case Frye v. United States. The Frye standard requires that a court decide if the procedure, technique, or principles used by the expert were generally accepted by a substantial proportion of the relevant scientific community. While many courts have abandoned the Frye standard for the standard provided in the Daubert v. Merrill Dow Pharmaceuticals, Pennsylvania continues to follow the Frye standard.
Why Do Attorneys Use Expert Witnesses?
Because expert witnesses are able to testify about their opinions and a wider variety of topics than fact or lay witnesses. Therefore, attorneys will use expert witnesses in cases that involve complicated facts. An expert witness’ opinion, based on their specialized training and experience, can assist the jury or judge in better understanding the complex issues.
For example, suppose a fact or lay witness is called to testify in a truck accident case about what they saw during the incident in question. They might say they saw the truck collide with the plaintiff’s car and cause serious damage to the plaintiff’s vehicle. However, the plaintiff’s attorney may employ an expert witness to “reconstruct” the accident or to investigate whether or not the truck’s brake system was defective and was the actual cause of the accident.
Similarly, attorneys in medical malpractice cases frequently use expert witnesses to show that a doctor committed malpractice by negligently performing a surgery, failing to properly diagnose a medical issue, or generally performing below the proper standard of care.
Also, judges or juries may view expert witnesses’ opinions as unbiased compared to other witnesses. For example, when a judge or jury is comparing testimony from a party’s family members to a third-party expert, the expert’s testimony may seem more objective.
Different Kinds Of Experts Witnesses
There are as many types of experts as there are types of cases. Which expert to use depends on the type of case and the type of issue that needs explanation.
Some of the more common types of expert witnesses include:
Medical experts include doctors, nurses, dentists, or any other medical professional. Medical experts usually testify in cases like medical malpractice, personal injury, or car accident cases. Medical experts are able to provide judges and juries with information about a plaintiff’s pain and suffering, the medical procedures the plaintiff had to go through, and the likelihood of the plaintiff’s recovery.
Mental Health Experts
Mental health experts are mental health professionals like doctors, nurses, psychologists, and therapists. They provide testimony regarding possible diagnoses for people or the effects of a mental health issue on people. Mental health experts may also testify regarding whether a person was of sound mind when they did something or whether they were able to form the requisite intent to perform a certain act.
These experts deal with whether and how a person can return to work. These experts are usually involved with discrimination, injury, and divorce cases. Vocation experts can offer their opinions on the amount of time it will take for someone to be trained for a certain skill or job and the amount of income that person can earn at the job.
These experts are usually design and engineering professionals. They typically testify in product liability, injury, and defect cases. Engineering experts can give opinions regarding complex issues regarding product design and safety.
Forensic experts testify in a wide variety of cases. The job of forensic experts is to apply their training and experience to understand what happened. For example, a forensic expert may be used to find data that someone attempted to delete from a computer, or even to reconstruct an accident scene.
Financial experts deal with financial issues in many cases. For example, in a divorce case, a forensic accountant will examine the party’s accounts to see if one of the parties was hiding assets or money. A financial expert may also testify in a business case to determine whether one of the parties was not upholding their fiduciary duties to their business partners. Financial experts may also deal with the valuation of certain assets in property damage cases.
Securities Experts usually testify in fraud cases. Securities experts can review the facts of a case, research the market at the time of the alleged fraudulent incident, and provide an opinion on whether someone committed fraud.
Parenting experts usually testify in family law cases like divorces, adoptions, and parental rights cases. Parenting experts use their training and expertise to provide an opinion about the child’s best interests.
Contact An Attorney For Help With Your Case
If your injury case has complex issues and facts, you may need an expert witness to strengthen your case. Contact an attorney for help with your claim. Your attorney can consult and collaborate with expert witnesses to help prove that another party is at-fault for your injuries.