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Law 101: Legal Guide for the Forensic Expert

Importance of Demonstrating Lack of Bias

Wherever possible, it is also critical to demonstrate the witness's lack of bias. For example, if a DNA analyst has also been called to testify for the defense or has participated in testing that has led to exonerations, this information will support and substantiate a claim of scientific neutrality.

The opposing party has the right to question (cross-examine) the expert regarding forensic or specialized credentials before the judge makes a determination as to the witness's fitness to testify.

In general, that questioning is likely to focus on bias, asking about:

  • The amount of money the witness is being paid for investigating and testifying.
  • The fact that the witness routinely testifies solely for one side.
  • The witness's lack of accomplishments in a particular area, such as academia or publications.

If the witness is known to have failed a proficiency test or has otherwise committed some demonstrable error, it is likely to become a subject of the cross-examination as well.

When the witness has strong credentials, it is not uncommon for the opposing party to shortcut the process by agreeing to stipulate to (i.e., concede to) the witness's fitness to testify as an expert. When this is offered, the smart attorney will still ask the court for permission to summarize the witness's credentials so that they can be enumerated for the fact finder.

If there is no stipulation, the judge will then make a determination as to whether the witness has sufficient background to permit their testimony as an expert. If the ruling is favorable, the lawyer for the party who called the witness now turns to the substance of that individual's testimony through questioning referred to as direct examination.

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Date Created: September 1, 2023