When defending against Arizona criminal prosecutions, understanding the nuances of expert testimony can be a game-changer in shaping the outcome of a case. The Arizona Court of Appeals recently released a ruling that helps to explain the requirements for a witness in a criminal case to testify as an expert. These standards and requirements may help a skilled attorney exclude harmful evidence from being admitted against their client by a proposed expert.
Expert testimony involves the presentation of opinions or conclusions by individuals with specialized knowledge, skill, experience, training, or education in a particular field relevant to the case. Unlike lay witnesses who testify about facts within their personal knowledge, expert witnesses provide professional opinions to assist the court in understanding complex issues.
The recently decided opinion involved a case where the defendant appealed convictions for aggravated assault, and the victim testified as to the source of damage to a vehicle. On appeal, the defendant argues that this was expert testimony that was improperly admitted at trial. In the recently released opinion, the appellate court discussed the factors that define expert testimony versus lay testimony.