Expert Witnesses Help Judges and Juries Find the Truth

Q: Why do people use "expert" witnesses in court?
A: The purpose of a trial is to bring out the truth about the matter in question, so that justice can be done.  To learn about the facts of a case, the judge or jury hears testimony from witnesses who have first-hand knowledge about those facts.  For example, Mary can testify that John shot her with his pistol, or Steven can testify that the paper being passed from juror to juror is the receipt that his landlord gave him when he paid the rent.  Where there is conflicting evidence about the facts, the judge or jury must decide which testimony is most likely to be true.  In many cases, an expert witness will be able to provide evidence that helps the judge or jury make those decisions.  For example, you know that a ballistics expert might testify that the bullet removed from Mary's arm came from the gun owned by John, and that a handwriting expert might testify that the signature on Steven's receipt was written by the landlord who denies signing it.  The expert is allowed to give his or her informed opinion about disputed or unclear questions of fact, on subjects outside the life experience of ordinary judges or jurors, because he or she has specialized knowledge, skill, experience, training or education on that subject.

Q: What kinds of things can experts testify about?
A: Experts testify about a very wide range of subjects - many more than can be mentioned here.  For example, if you are injured in a fall at work when you are trying to escape a fire, a doctor may testify as an expert that your persistent headaches are a direct result of that fall.  If you are suing the manufacturer of the machine in which the fire began, an electrical engineer may testify as an expert that the fire was caused by a short-circuit, and may explain how the machine could have been designed to eliminate that risk.  If you are sued for causing an automobile accident, a specially trained police investigator may testify, based on the skid marks and the damage to the vehicles, that the other driver was traveling much faster than he or she claims.  If your mother has been damaged because of inadequate services rendered by her dentist, her auto mechanic or her Realtor, the trial will almost certainly include testimony from another dentist, auto mechanic or Realtor who can inform the judge and jury about the standard, accepted professional practices of such persons in your area.  If your neighbors are getting a divorce, a laboratory technician might testify, based on blood testing, that in her opinion the husband is not the father of the youngest child, and an accountant might testify about the value of the family restaurant business and of other assets that the court will divide between the divorcing parties.

Q: If I ever have to go to court, how will I know whether I need an expert, or how to find one? Who pays for the expert?
A: Talk with your attorney about whether you need an expert witness to support your case.  Experienced attorneys usually know or know of experts in the subject of your dispute who can study and evaluate your case and testify on your behalf, if necessary.

In some cases experts are paid by a public agency (the court or the prosecutor, for example), and if you are represented by a lawyer hired by your insurance company your insurer will pay for any necessary expert witnesses.  However, in most cases you will be responsible for paying any expert who works on your case.  Talk with your attorney about how much the expert will charge and when the expert will have to be paid.  Some lawyers, in certain kinds of personal injury cases for example, will pay these expenses for you as they are incurred, with the understanding that you will reimburse them out of the proceeds of the lawsuit. Money is well spent on the services of an effective expert witness.  In many cases that witness will provide evidence that is essential to proving your case, and even in cases where such testimony is not strictly necessary the expert may help the judge and jury understand your side of the case and therefore help persuade them of the justice of your cause.


Law You Can Use is a weekly consumer legal information column provided by the Ohio State Bar Association. This article was prepared by David S. Cooper,  B.A., J.D., of Worthington.

Articles appearing in this column are intended to provide broad, general information about the law. This article is not intended to be legal advice. Before applying this information to a specific legal problem, readers are urged to seek advice from a licensed attorney.



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