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Law 101: Legal Guide for the Forensic Expert

Experts Can Give Their Opinion

An expert witness is the only witness permitted to give their opinion in testimony. The expert may do so only after the following conditions are all met to the satisfaction of the presiding judicial officer:

  1. The expert's opinions are likely to be helpful.

  2. The expert is able to provide an opinion based on specialized education, training, experience and knowledge.

  3. The expert is able to speak about methods, instruments and techniques established and relied on throughout the expert's peer community.

  4. The expert is able to demonstrate that only accepted and reliable methods were used in the specific case.

  5. The expert is able to identify evidence that he or she has personally examined.

The sufficiency of all predicate or foundational evidence is a legal determination, typically made by the judge.

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