How Different Is Expert Witness Testimony From An Ordinary Witness Testimony

Witnesses play one of the most important parts in all kinds of cases - from criminal to personal injury. They help clarify what happened by revealing the information about the matters of the case to the judge or the jury.

Whenever someone answers a question under oath during a trial or a deposition, they are considered by the law as witnesses and the statements they make are considered testimony. 

However, not every witness is the same. There are two types - expert witnesses and ordinary (or lay) witnesses. This fact affects whether the testimony will be permissible as evidence.

Today, we’ll take a deeper look at both types of witnesses and explain what expert witness testimony is and how it differs from regular testimony.

What Is Lay Witness Testimony?

These witnesses are often in close relation to the case. For instance, they may be business partners of one of the parties, family members, or more commonly, eyewitnesses that were present on the scene.

The lay testimony is governed by the Federal Rule of Evidence 701, under which lay testimony must be:

1. Based rationally on the perception of the witness

2. Helpful for determining the facts of the case

3. Not based on specialized, technical, or scientific knowledge

According to the law, ordinary witnesses can only testify about their firsthand knowledge of the facts of the case. This means they can only relay information to the court that they have gained through personal knowledge or perception that is rationally based.

Since they can testify in different matters, the definition of what constitutes personal knowledge can be comprehensive. Typically, an observation of an event does fall within the realm of what can be defined as personal knowledge.

This could be a firsthand account of a car accident or a crime.

Additionally, lay witnesses are allowed to testify about their perception of the events in the case if they obtained the perception through earlier observation. For example, they can offer an opinion about a person’s appearance, degrees of light, distance, etc.

These perceptions must be based on rationality, but the standard here isn’t that strict as lay witnesses are allowed to use everyday logic to come to conclusions in their testimony.

Normally, lay witness testimony and opinions don’t need to be summarized or disclosed before the trial commences. The only exception is when the regular testimony starts threading the line between a lay and an expert witness testimony. In those cases, the lawyer has to ensure that testimony can be admissible in court. 

For instance, they may disclose the opinion of the witness to the other party or strike up an agreement with them about the disclosures they need to provide.

What Is Expert Witness Testimony?

An expert witness is an individual who has experience and skill sets that can help the jury or the judge understand the factual evidence of the case.

Since these individuals don’t have immediate knowledge of the events that transpired, they use their expert methodologies and technical knowledge to form a reasonable opinion on the case. 

Expert witness testimony is governed by the Federal Rule of Evidence 702 which sets out different standards than in lay testimony. An expert opinion is only admissible in court if it was supplied by a witness that is qualified as an expert and has training, education, experience, knowledge, or skill.

Furthermore, according to Rule 702, the expert witness testimony has to meet the following requirements:

1. Knowledge of the expert can help the judge or the jury determine a fact or understand the evidence

2. Expert witness testimony is based on data and facts

3. Testimony was produced through reliable methods

4. Expert has applied all the methods and principles to the evidence or facts

While this rule seems restrictive, experts can still provide their own opinion. For instance, they may testify about generally accepted principles, information, or methods if they are relevant to the case matter.

Standards Applied To Expert Witness Testimony

The standards are usually higher for expert witness testimony. For example, according to Federal Rules of Civil Procedure that apply to most states, lawyers have to meet disclosure requirements that aren’t required for regular witness testimony. 

Rule 26(a)(2) dictates that experts retained by attorneys must submit an expert witness report (this rule sometimes applies to consulting or non-testifying experts). 

An expert may also be deposed by the opposing party. The questions in this deposition usually clarify the qualifications, methodology, and key assumptions outlined in the expert witness report. 

The opposing party can also use the deposition as a chance to condense the scope of the testimony by establishing the topics that the expert won’t testify about during the trial.

Anything an expert reveals or says during the deposition can be potentially used to impeach them later on. This means that the testimony can’t be inconsistent with the testimony at the trial.

In most cases, the judge will be tasked with applying the Daubert standard to establish if the expert witness testimony is properly applied to the issue at hand and if the testimony uses valid scientific reasoning.

More precisely, the judge will determine the following:

1. If theories or techniques from the expert witness testimony can be tested

2. Whether the theories or techniques have been peer-reviewed

3. If there are necessary standards that the techniques adhere to

4. Whether the scientific community accepts the theories/techniques

Retaining An Expert Witness

Experts can fill many roles in the litigation process, but more often than not, they are considered either consulting or testifying experts. The former are usually retained by one of the parties in anticipation of a legal process while the latter may present evidence at the trials.

In other words, consulting experts help attorneys prepare the best case possible.

Since expert witness testimony is usually put under a great deal of scrutiny and their qualifications are contested, your choice of expert matters. Choose only an expert witness that has experience in the area related to the case.

You should also review their prior testimony to see if they were previously disqualified in a similar case. If that’s the case, they’re not a good choice as their disqualification will be raised as a point in the trial.