Forensic, General & Medical
Expert Witnesses

Pretrial Role of Expert Witness Testimony


The expert witness has several duties to perform before he or she will testify in the courtroom before a jury or a judge, and some of these duties involve the testimony review before the courtroom event. Some experts may need to create a report that the judge or opposing legal counsel will have access to before the trial starts.

There are several roles that expert witnesses take for cases. These may involve siding with the prosecution for criminal matters or siding with the defendant in the same issue. However, the expert may also have a pivotal role in litigation claims for or against the plaintiff. In many of these situations, the professional will create a report and use his or her knowledge to test out evidence through certain methods. These are generally part of pretrial activities. They work to help the expert create his or her testimony for the overall case or claim. The tests also help him or her form an opinion based on evidence.

Testimony before the Judge

When an expert witness is part of a case, he or she will generally provide testimony related to the case to the judge and opposing legal counsel before the trial starts. The pretrial testimony may then require testing and questions by each party to determine if it is valid, reliable and relevant enough to the subject material of the case. Even if the expert is not the primary person used for the evidence, he or she must have some sort of relevance to the information and details of the case. Additionally, he or she must use testing methods that have reliable results with no more than a five percent error rating. The person usually needs to have some scientific standing with the community and have papers reviewed by peers.

The Testing Process

One of the most important aspects of an expert witness with a scientific background is the testing process. He or she may provide results from this before the trial begins, or he or she may even start testing evidence before he or she faces the judge or opposing legal counsel to determine if he or she will remain a designated expert witness for the case. Some testing may provide results for the validity of items such as DNA or analysis that runs through a computer program. The end result should ensure that no more than a five percent error rate occurs when using such methods. If a report is necessary for the case or claim, the professional will add any details from the testing and any opinions about the process.

If the expert witness must engage in the testing methods, he or she will generally need to supply the courtroom with the results. These details present through testimony during the claim or case. The expert witness will often need to explain the results as if he or she were speaking to an average person with little knowledge about the subject matter. He or she may even have the potential to connect the defendant to the scene of a crime or liability in a civil case. Proof through the testing process is not irrefutable, but with confidence in the processes, the expert may increase the assurance with the judge or jury in the results.

The Report and Examination

When an expert must provide a report for the legal proceedings, he or she must include several elements. These generally consist of the details of the case, the testing process, results, error rates, opinions of the professional as well as the conclusion of the matter. Some reports may also have some of the testimony the expert may provide in the courtroom. As part of the process, the expert witness will provide the document to the lawyer that hired him or her and the judge. Both will review it and additions or modifications may become necessary.

The judge may examine the testimony that an expert witness may present in the courtroom through the report or in person. This is to ascertain relevance, reliability and consistency. Any problems with the testimony before the trail or claim proceeds and the expert may lose his or her qualification as a designated expert witness in the case. This action occurs with greater frequency for a defendant in criminal cases and a plaintiff in civil cases due to the details in the testimony or credentials of the expert. It is vital to pass the examination and ensure that testimony is relevant, reliable and valid.


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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