Expert witnesses are not summoned just from their words alone. Their testimonies are based on sufficient facts and data, and a product of reliable methods and principals. They must prove their scientific opinions in forms of validated consensus in the science community. Expert witnesses must also prove their technical, educational, and specialized knowledge by presenting their training history and experience. ("Rule 702. Testimony by Expert Witnesses")
Fire investigators are, in fact, experts because they apply the scientific method and facts to formulate their expert opinion. While fire investigators made mistakes in the past involving the conviction of George Souliotes, they based their conclusions on science known at the time and the standards of evidence admissibility just was not as strict as it is today. Advancements in both science and federal law are evidence that fire scientists are much needed in forensic science and they are significant in our legal and justice