Forensic, General & Medical
Expert Witnesses

The Five Daubert Factors in Expert Witness Testimony


The Daubert factors are important for expert witness testimony, and when followed appropriately or applied to an expert, it may reduce or eliminate the possibility of a Daubert challenge from occurring. Reliability and relevance to the subject are the two most important categories, and the five factors that fall under these affect the case from various angles.

The five Daubert factors are methods and procedures that may be tested, the known and potential rate of error in these processes, if they have been subjected to peer review by the expert’s peers in his or her field, if there are standards that control the operation of techniques and the acceptance of the methods used in the relevant scientific community. These factors are important for the scientific experts, and without their inclusion the professional may not be considered an expert witness. He or she must ensure that processes used to connect evidence or to test certain theories may be reproducible and tested by others.

The error rate is of significance in how it must not change, or it could affect the test process.
When an expert is hired for a claim, he or she should have already connected all five factors to his or her professional life. This then permits him or her to continue as an expert in his or her field of study for current and future projects. The Daubert challenge becomes null, and the expert may retain his or her qualifications in the courtroom. Additionally, these factors affect the methods, testing and connecting of evidence to the defendant or plaintiff. He or she may then form a solid opinion based on facts and proven processes.

The Factors Applied in Court

When an expert is hired, he or she is there to provide a connection to evidence, unravel the confusing aspects of a case and testify in the courtroom about his or her opinion of the claim. Through his or her methods used, it is possible to determine the most likely cause or course that occurred or affected the plaintiff or defendant. This places faith in the professional and weight on his or her words. Because of this, he or she must follow tested methods where the error rate is not a fluctuating problem. The control and understanding of these processes is vital to producing verifiable and reproducible conclusions.

An acceptance and peer review of these methods helps the expert further his or her understanding of how to proceed in the scientific community. Additionally, he or she is able to instill confidence when his or her methods are reliable and relevant to the subject matter. Then, the judge or jury are not worried that the tests, analyses or examinations are in error. A reconstructed accident has certain facts connected, and the expert is able to remove various confusing pieces of information. This is especially important when applying liability and when compensation becomes part of the dialogue.
The Expert Witness and the Factors

To prevent the possibility of a Daubert challenge succeeding, the expert is tasked with presenting and adhering to the five factors as well as the two categories that govern his or her professional conduct and processes. Without ensuring the methods are reliable, they cannot be tested properly. This then could affect the error rate and whether someone else could reproduce the process. Peer review and acceptance into the community with the procedures are way to control what is used in the courtroom and how the evidence is assessed. These factors keep the expert honest and to a higher standard.

To exemplify what it is to be an expert, the professional must ensure his or her opinions, processes and reports are all relevant, have the pertinent facts and are utilized for the claim. It is possible to include extraneous data and information that appears unrelated provided there is a basis for it and it is directly connected to the claim of the plaintiff or defendant. It is vital that the testimony of the expert witness is admissible, and this is only possible by complying with the factors, presenting satisfactory credentials and keeping with the categories of reliability and relevance.

The Expert’s Testimony with the Five Factors

When the five factors have been followed properly and through all channels, the expert’s testimony relates to the case appropriately and is used to remove confusion, clarify details or for a scientific method. Then, the expert witness may demonstrate a process or provide more information about the claim.


Provided by HG.org


Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.

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