By The Honorable Earl G. Penrod

MOST LAW ENFORCEMENT OFFICERS WHO are called upon to testify are highly trained and skilled professionals. Through their education and experience, officers effectively assess and investigate a variety of circumstances and arrive at appropriate opinions and conclusions. However, during testimony, officers are sometimes surprised when they are prohibited from providing an answer because it improperly calls for the officer’s opinion.

The rules of evidence in most jurisdictions distinguish between expert witnesses and lay witnesses by permitting expert witnesses to testify in the form of opinions while limiting lay witnesses to testimony about facts and observations. Although this distinction is generally accurate, it can be confusing and misleading. After all, police officers are well-trained professionals and being referred to as a “lay witness” may appear to minimize the officer’s credentials and level of experience and training.

The prohibition against providing opinions is not simply a matter of whether a witness has been qualified as an expert. A lay witness may testify in the form of an opinion if the opinion is rationally based on the witness’s perception and is helpful to the judge or jury in understanding the witness’s testimony. However, if the opinions require scientific or highly technical knowledge, the officer will not be permitted to offer such opinions unless it is shown that the officer has acquired the necessary scientific or technical knowledge through skill, experience, training or education.

Police officers and other non-expert witnesses can testify in the form of an opinion when the opinions are based on personal observations. Scientific or technical knowledge is not required for opinion testimony on issues such as weight, size, speed, distance and appearance. After an officer has testified about his or her observations, the officer may testify that in the officer’s opinion, the defendant appeared to be intoxicated.

Some police officers undergo specialized training and education to become an expert in certain aspects of law enforcement and, as a result, may testify in the form of opinion evidence in the areas in which the officer has been qualified as an expert.

TIP TO TESTIFY: Whether testifying as a lay witness or as an expert, an officer should always be prepared and professional on the witness stand.

The Honorable Earl G. Penrod is the Senior Judge for the Indiana Office of Court Services and the American Bar
Association Judicial Fellow in cooperation with NHTSA.

Have a testimony topic you would like to see addressed? Contact Judge Penrod at

This article originally appeared in the April 2017 issue of The LEL.