Background and Qualifications

Rule 702(a): “a witness qualified as an expert by knowledge, skill, experience, training, or education…
Introduce the witness to the jury, and demonstrate the witness’s expert qualifications.

  1. Name, basic introduction, background?
  2. Job title, location, description, years of experience?
  3. Previous employment, length of time?
  4. Education, formal training, other practical or personal study?
  5. Licenses, certifications, awards, honors?
  6. Publications, papers, presentations?
  7. Prior qualification/testimony as an expert witness, number of times, in what field?
  8. Any other relevant qualifications/experience/background/curriculum vitae?

“Your honor, the state tenders Mr./Ms. Witness as an expert in the field of….” (youth counseling, molecular biology, general automotive knowledge, criminal street gang terminology and practices, etc.).

Reliable Principles and Methods

Rule 702(a)(2): “the testimony is the product of reliable principles and methods”
Give the jury a basic understanding of the witness’s field of expertise, explain how and why certain tests or practices are done in this field, and illustrate the reliability and accuracy of the expert’s work.
“Mr./Ms. Witness, before we get into the specific details of this case, let’s talk about what is involved in [the field of “X”] and how it’s done….”

  1. Explain what someone who works as “X” does?
  2. Overview of the background/principles/theories/methodologies in the witness’s field?
  3. Explain the procedures/equipment/technique involved in any testing/analysis?
  4. How is that testing/analysis/process verified? peer review? confirmation? accuracy?
  5. Witness’s personal experience: how many times? for how long? how often per week/month?
  6. Witness’s personal experience/observation/confirmation which shows accuracy/reliability?
  7. Any other relevant questions which demonstrate reliability of principles/methods?

Sufficient Facts and Data, Applied to This Case

Rule 702(a)(1), (3): “the testimony is based upon sufficient facts or data” and “the witness has applied the principles and methods reliably to the facts of the case”
Show the jury that the principles and methods just described were actually utilized and followed, and there is a solid foundation for the expert’s opinion in this case.
“Mr./Ms. Witness, now that the jury understands what is involved in [the field of “X”], let’s discuss the work you were asked to do in this particular case….”

  1. Explain how witness became involved: when, how, why, nature of request/inquiry?
  2. What information/material were provided to the witness for analysis?: introduce (or show to witness, if already introduced) any relevant samples, pictures, swabs, etc., and verify the identity of the exhibits as the items actually examined/tested?
  3. What did the witness do with that information/material?: walk the jury through the specific application of the general procedures previously described, and confirm that samples/items were adequate to allow for proper analysis/testing in this case?
  4. Explanation of results: quantify, show, discuss, present – what did the testing/analysis reveal or indicate in this particular case?
  5. Follow-up analysis, if any: confirmed by a supervisor, secondary testing, verified by other means?
  6. Any other relevant questions necessary to explain how analysis/testing was done in this case, and what the results were?

Opinion or Conclusion Questions

Rule 702(a): “if scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert…may testify thereto in the form of an opinion, or otherwise…”
Ask the witness to tell the jury what conclusions or opinions the witness was able to make which are relevant to the facts at issue (this weapon could have caused the victim’s wounds, the vehicle must have been speeding, clothing fibers conclusively match the samples found at the scene, etc.).
“Mr./Ms. Witness, based on your training and experience, and the testing and analysis you performed in this case, do you have an opinion, to a reasonable degree of [scientific/medical/professional/etc.] certainty, whether….?”

  1. Primary opinion: is it a match? positive test result? correct fit? accurate assessment?
    (Or, for subjects where the answer is not simply a yes/no or positive/negative opinion – what is the likelihood? percentage? probability? confidence level? degree of inclusion or exclusion?)
  2. What is your basis for reaching that opinion/conclusion? (Gives witness an opportunity to summarize and recap complex issues for the jury.)
  3. Offer/introduce any additional exhibits: final report, summary charts, etc.
  4. Hypothetical opinion (if helpful): how would results/opinion be different if the facts/data/samples were different?
  5. Exclusion opinion (if possible): could not have been anyone else, no other way it could have happened, only possible conclusion based on testing/results, etc.?
  6. Any other relevant questions necessary to explain the witness’s opinion or conclusion, and how it has a bearing on a fact in issue in the case?