Forensic evidence and testing relates to the analysis of evidence obtained from the crime scene through a vastly technical or scientific process (Buckles, 2007). Such as so, it requires a highly trained or skilled person to do the analysis; such persons for evidentiary purposes are referred to as expert witnesses. Expert witnesses are very critical in the criminal justice as without their expertise a lot of crimes would remain unresolved (Saferstein, 2011). However, due to the technical nature of the evidence, it is difficult to ascertain the authenticity and admissibility of such evidence.
Accordingly, there are basic standards set to guide the reception and admission of expert evidence. These standards are set by evidence law and case law (court decisions). It is worth noting that though different courts have different rules, the standards set for admissibility of expert testimony generally apply across the board. Before getting to the tests, it is imperative to note that the law defines who an expert is thus the expert evidence can only relate to matters within the expert’s knowledge.
There are three standard tests used to establish admissibility of expert testimony: the general acceptance test, the reliability test, and the Daubert standard (Buckles, 2007). The general acceptance test was established in Frye v. United States; hence the test is also referred to as the Frye test. In the case, the court ruled that forensic evidence obtained by a scientific test or procedure is only admissible if the procedure or test itself has attained general acceptance in the field it belongs. This test requires that the scientific test be generally accepted in the scientific community as reliable.
In applying the test, the court determines whether there are other experts who recognize the test or procedure as reliable. The court my additionally look at books and papers published in relation to the subject (Saferstein, 2011). Essentially this test focuses more on the acceptance by other experts than the relevance and evidential value of the evidence. Though this test is appropriate for established procedures, it is insufficient in relation to new scientific procedures.
The reliability test was developed from Federal Rules of Evidence and is meant to deal with the shortcomings of the Frye test. It requires that the forensic evidence be reliable and relevant. In applying this test, the court weighs the reliability and evidential value of the test or procedure against the test or procedure’s likely prejudice. Key considerations the court takes into account are the relevance and reliability of the test or procedure, whether receiving the evidence would confound, or hoodwink the jury, and the nexus between the test or procedure and the facts in issue.
This test has been applied differently in different states. Some apply it with the Frye test others modify the Frye test with it. The general consensus is however that forensic evidence would be admitted if it is relevant and of probative value to the case. Accordingly, it differs with the Frye test to the extent that it may allow new techniques that are not necessarily generally accepted.
The Daubert standard was established in Daubert v. Merrell Dow Pharmaceuticals, Inc. The court in applying Rule 702 of the Federal Rules of Evidence rejected the Frye test’s general acceptance as the absolute basis of admitting forensic evidence. The court emphasized reliability and relevance ruling that the judge should act as a ‘gate keeper’ to ensure that expert evidence admitted is relevant and reliable (Buckles, 2007). Reliability in this context requires the test or procedure to rest on reliable foundation and not necessarily on general acceptance. This test is flexible and may apply to both established and new scientific techniques.
Buckles, T. (2007). Crime Scene Investigation, Criminalistics, and the Law New York: Thomson
Delmar Learning. Print.
Daubert v. Merrell Dow Pharmaceuticals, Inc, 509 U.S. 579 (1993)
Frye v. United States 293 Fed. 1013 (D.C. Cir. 1923)
Saferstein, R. (2011). Criminalistics: An Introduction to Forensic Science (10th Ed) New Jersey:
Prentice - Hall. Print.