Discovery is the process where the prosecuting attorney provides defense counsel with an opportunity to view, copy, or test the evidence in the government's possession. The discovery process is governed by state statutes, rules of procedure, and case law. The discovery process includes certain materials that are in the possession of its experts. The process is not automatic and the scope of disclosure of discovery materials varies from state to state and court to court. The discovery process is not unilateral and does impose responsibilities upon the defense to disclose certain information to the prosecution.
Evidence & Admissibility
In general, admissibility is the legal concept that determines what evidence, both testimonial and physical, will be admitted by the court and the jury will be permitted to hear. Admissibility is determined by statute, rules of evidence, and case law. This particular aspect of admissibility relates solely to the admissibility of the science or subject matter at issue and not to the qualifications of the individual.
With respect to scientific evidence, three distinct "tests" or "standards" have evolved. They have become known by the case names from which they originated. The "Frye" test originally involved testing from a polygraph type of instrument. The "Frye" test was also referred to as the "general acceptance" standard since it required the methods and techniques to be generally acceptable within the relevant scientific community.
Subsequent to the "Frye" test was a case that resulted in a new standard being established by the courts. "Daubert" shifted the determining factor of admissibility away from the "general acceptance" of the relevant scientific community to the "gatekeeper" concept. Under "Daubert" the presiding judge would act as the "gatekeeper" and determine whether or not the proposed evidence was relevant, applicable to the case and would be helpful to the jury.
Other "hybrid" states have either adopted legislation or rules of evidence that modify or alter in some way either the "Frye" or "Daubert" standards. The number of states that uses either the Frye or the Daubert standard fluctuates over time.02
Generally, unless an express exception exists, opinion testimony is not admissible in court. Expert witnesses may, if qualified and recognized by the court, give their opinion. The proponent of the evidence must establish the qualifications of the expert witness from whom they will seek opinion evidence in court.