Many readers may be wondering when it might be useful or necessary to employ an expert witness in a criminal case. For some cases, expert testimony may not be helpful — as, for example, in a simple drug possession case where the drug test is not in question, or in simple battery or assault case. In other types of cases — such as sex offenses or violent crime — retaining an expert witness can mean the difference between a guilty verdict or not guilty verdict, or the dismissal or indictment of a charge. With an allegation of child abuse or molestation, for example, an expert opinion on the techniques used in a forensic video can be invaluable. Similarly, a guns, weapons, or DNA expert may be crucial in a murder or aggravated assault case.
Unfortunately, sometimes the question in cases is not whether an expert would be helpful, but whether a client can afford to hire an expert in a case. An attorney can help you decide how crucial an expert may be for your chances at success, and how expert testimony may be useful to you in your case strategy.
Who Can be Qualified to Testify as an Expert Witness?
The trial judge ultimately decides who can testify as an expert. Georgia courts are generally quite liberal in allowing individuals to testify who demonstrate sufficient education, training, or experience in a certain field of study. For example, medical doctors are usually considered experts by Georgia courts. Similarly, forensic scientists at the Georgia Bureau of Investigation are routinely qualified as experts. In addition to being qualified, the science on which an expert opinion is based, must reach the appropriate legal standard.
O.C.G.A. 24-7-707 provides that in criminal proceedings the opinions of experts “on any question of science, skill, trade, or like questions shall always be admissible.” The Georgia Supreme Court in Harper v. State (249 Ga. 519 (1982)) puts a limit on the scientific procedures or theories an expert opinion relies on. Rather than calculating the consensus in scientific community, Harper leaves it to the trial judge to determine whether a given procedure or technique has “reached a scientific stage of verifiable certainty, or . . . whether the procedure ‘rests upon the laws of nature.'”
In short, an expert’s opinion must be based on scientifically valid methods that pass the Harper standard. If an attorney suspects that an expert’s methods do not pass the Harper standard, he or she can file a motion to exclude the testimony.
Expert witnesses play an important role in many jury and bench trails across the state. Jurors and judges both are often greatly influenced by the testimony of expert witnesses. Whether you are calling an expert to testify in your defense or attacking the credibility or methods of the state’s expert, a thorough understanding of Georgia expert witness law is essential to any good defense. Contact our office today for a free consultation if you have any questions regarding the law of expert witnesses in Georgia.