Expert Testimony

in Modern Legal Practice

Studying the rules of evidence is one thing, applying them in the real world is another. Law students and lawyers read and memorize the rules until they can cite them in their sleep, yet often still struggle to utilize them appropriately during hearings or trials.

This struggle isn't incompetence. During trial, attorneys must juggle countless tasks: managing witnesses, adapting to unexpected testimony, gauging jury reactions, establishing case elements, and guiding nervous witnesses through testimony to coax out vital pieces of information in order to adequately meet their burdens of proof.

It's like herding cats through a sea of herring while ensuring none of them eat anything.

The Value of Expert Witnesses

Expert witnesses can significantly strengthen a case. They typically have testifying experience, making them less prone to nerve-induced memory lapses. As professional witnesses they can maintain their testimony's focus under the pressures of trial and are usually fairly reliable.

My first experience with an expert witness was in my very first trial and it demonstrated their value immediately. While interviewing a psychiatrist who treated my client (an abused child), he stated, "the opportunity to help children is a perishable one." This perfectly captured what I needed the factfinder to understand - we needed to help this child now, not later, because the longer the child continued to be unhelped the more damage was being done. I asked the expert to repeat this during testimony and made his statement the core theme of my case, incorporating it into my opening and closing arguments. By the end of the trial the factfinder had heard me say "the opportunity to help children is a perishable one” in my opening, had heard the expert say it on the stand during his testimony, and had heard me circle back to it in closing.

Proper expert witness preparation can transform their testimony into a compelling component of your case.

Modern Rules Governing Expert Testimony: FRE 702-705

RULE 702: Testimony by Expert Witnesses (as amended Dec. 2023)

A witness qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the proponent demonstrates to the court that it is more likely than not that:

(a) the expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert has reliably applied the principles and methods to the facts of the case.

RULE 702 in plain English:

A qualified expert can give opinions about facts outside everyday knowledge if you can show the court it's more likely than not that:

1. The expert's specialized knowledge will help the factfinder

2. Their opinion is based on sufficient information

3. They used reliable methods

4. They applied those methods properly to this case

The 2023 amendment clarified that the proponent of expert testimony must demonstrate admissibility by a preponderance of evidence standard ("more likely than not").

Experts come in many forms - not just doctors or specialists with advanced degrees. Expertise can develop through experience. For example, a police officer can testify as an expert on intoxication based on extensive experience with intoxicated individuals, even without formal alcohol abuse training.

RULE 703: Bases of Opinion Testimony by Experts

The facts or data experts base opinions on may be those they personally observed or learned before/during the hearing. If experts in the field would reasonably rely on such facts/data, they need not be admissible for the opinion to be admitted. However, inadmissible facts cannot be disclosed to the jury unless their value in helping evaluate the expert's opinion substantially outweighs their prejudicial effect.

Rule 703 in plain English:

Experts can form opinions using both admissible evidence and some inadmissible information that experts in their field typically rely on. However, they generally cannot disclose the inadmissible information to the jury. This prevents attorneys from using experts to introduce inadmissible evidence.

RULE 704: Opinion on Ultimate Issue

(a) An opinion is not objectionable just because it embraces an ultimate issue.

(b) In criminal cases, expert witnesses must not state opinions about whether the defendant did/didn't have a mental state or condition constituting an element of the crime or defense. Those matters are for the trier of fact alone.

RULE 704 in plain English:

Experts can offer opinions on ultimate issues before the court. However, in criminal cases, they cannot testify about a defendant's mental state regarding the crime.

Example: A doctor can testify that workplace activity could have caused death, but cannot testify about a defendant's criminal intent.

RULE 705: Disclosing Facts or Data Underlying an Expert Opinion

Experts may state opinions without first testifying to underlying facts/data, unless the court requires otherwise. They may be required to disclose these facts/data on cross-examination.

Rule 705 in plain English:

Experts can give opinions without first detailing all facts they relied on, unless the court requires it. However, they may have to disclose this information during cross-examination.

The Daubert Standard Today

The Daubert trilogy (Daubert v. Merrell Dow Pharmaceuticals, General Electric v. Joiner, and Kumho Tire Co. v. Carmichael) established modern expert testimony standards. These principles have been incorporated into the Federal Rules of Evidence and adopted by most state courts.

When evaluating expert testimony today, courts typically consider:

1. Reliability: Has the theory/technique been empirically tested?

2. Peer Review: Has the expert's methodology been subject to peer review and publication?

3. Error Rate: What is the known/potential error rate and are there controlling standards?

4. General Acceptance: Is the methodology generally accepted within the relevant scientific/professional community?

5. Relevance: Does the testimony connect to the specific facts of the case?

The 2023 amendment to Rule 702 addressed concerns about inconsistent application of Daubert standards by emphasizing that judges must act as gatekeepers and explicitly requiring proponents to demonstrate admissibility by a preponderance of evidence.

Conclusion

Expert witnesses remain invaluable resources during trial. They can help establish case themes, provide memorable testimony, and support your position with credible specialized knowledge. To maximize their effectiveness, invest substantial preparation time with your experts before trial - listen to what they have to say and see if any of their nuggets of wisdom make a good theme for your case. You can’t lead their testimony but you can ask them to be sure to repeat something they’ve told you at trial.