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Expert Witnesses

How to Qualify an Expert Witness

The requirements for qualifying an expert witness are different from jurisdiction to jurisdiction. For example, in many jurisdictions an expert must be formally tendered as such and accepted by the court before being allowed to offer opinion testimony.

However, in other states, like Florida, as long as the foundation is properly laid, one may immediately begin questioning the expert as to his opinions without a formal tender and continue to do so unless the opposing party objects and requests an opportunity to voir dire the witness.

Nevertheless, some general elements of expert witness qualification tend to be the same throughout. The following questions are simply an overview of possible questions one may use to qualify an expert in most jurisdictions. It is by no means exhaustive, nor applicable to every situation or jurisdiction. Indeed, laying the foundation for the admissibility of expert witness testimony requires careful preparation. The required showing will vary depending on the subject matter of the expert's testimony, the extent to which the expert’s field of expertise is novel, whether it
involves hard or soft science and the connection between the expert’s qualification and the opinion offered.

The true art of qualifying/challenging an expert comes in paying attention and adapting to the witness's responses. The response to each question will often point to additional lines of inquiry.


1. What is your occupation/profession?
2. What is your educational background?
3. What degrees, certificates, or licenses do you have?
4. Have you attended or conducted continuing education seminars, conferences and related training?
5. Are you a member in any professional organizations/societies?
6. Have you received any awards or other professional recognition?
7. Have you published articles in your field?
8. How many cases involving [subject matter] have you handled?
9. How many years have you worked in this field?


1. What are the key principles that a person without education or experience in this field
would need to grasp in order to understand this case?
2. Can you explain the [research/theoretical basis/concept/scientific principles] involved in
this field of study to the jury/judge?


1. Have you examined or interviewed [the subject of the opinion]?
2. Have you conducted any tests on/interviewed [the subject of the opinion]?
3. Have you reviewed any records / documents / photographs / reports / recordings of [the subject of the opinion]?
4. Have you reached any conclusions as a result of your investigation?
5. Did you rely on any other source of information in forming your opinion other than the
materials that we have discussed?
A. If so, what other sources did you rely on?
6. If the facts were [supply hypothetical], could you render an opinion regarding [theory of case]?
A. If so, what is that opinion?



1. What theory/technique did you base your opinion on?
2. How did you test this theory/technique?
3. What were the results?
4. How many times have you used this theory/technique?
5. Have you always used the same method when you used this theory/technique?
A. Have you ever had different results, or results inconsistent with the theory/technique you
based today’s opinion on?

Extent of Subjective Interpretation

1. Does any part of the theory/technique require subjective interpretation?
A. If yes, describe what facet of the testing is subjective.
B. If yes, do you believe another professional might interpret the same data differently?
2. Is there any method you use to assess the subjective component of this theory/technique?
3. Did you use that method in arriving at your opinion in this case?

Peer Review

1. Has there been peer review of your theory/technique?
2. Has the theory/technique you rely on today been published?
A. If so, where and when?
3. Have any articles or other publications criticized or cast doubt on your theory/technique?
A. If so, when and what was the basis for the criticism?
4. Does that criticism change your opinion in this case?
A. Why not?

Error Rate

1. Does your theory/technique have a known or potential error rate?
A. If yes, what is the error rate?
B. How did you calculate the error rate?
2. Have you considered alternate theories or explanations?
3. Why did you reject any alternate theories or explanations?

Acceptance in Scientific Community

1. Is this technique/theory generally accepted in the scientific community of [expert's profession]?
2. What evidence is there that this is a generally accepted technique/theory?
A. Offer formal statements of professional organizations
B. Offer professional literature, training, publications
C. Show use by government/trade/community organizations

Use Outside Courtroom

1. Is this technique/theory used for a purpose outside the courtroom and litigation?
A. Describe various uses


1. What is your field of expertise/specialty?
2. Within the [mental health/social work/social sciences/other discipline] field, is this a recognized professional area of expertise?
3. Are there published articles recognizing this field of expertise/specialty?
4. Has this field of expertise/specialty been recognized by any licensing or accreditation body or any governmental agency?
5. Are there professional journals or conferences that focus on this field of expertise / specialty?
A. Is there controversy within the profession about the efficacy or reliability of this field of
expertise /specialty?
(1) If so, can you articulate why these [opinions/statements/criticism] should not undermine the value of your opinion?


1. Based on your education and experience, are you able to give an opinion as to_______________?
2. Within your [field of expertise/specialty] is it common for a practitioner to give an opinion as to [basis for opinion]?
3. What facts or evidence did you rely on?
A. Did you rely on [any materials not covered in previous answer]?
4. Is this the type of evidence relied on in the ordinary course of business by professionals in your field?
5. Is there any other evidence or information relied on in the ordinary course of business by professionals in your field as part of making such a determination that you did not use?
A. If so, what is it?
(1) Why did you not rely on this?
B. If not, why not?

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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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