The Cannabis Expert Witness

For the past few years, I have been engaged as an expert witness on a series of cannabis litigation matters here in Oregon. The way litigants use experts varies across jurisdictions due to local rules of evidence and other factors, but in any jurisdiction, compelling expert testimony can make or break a case. In this post, I will explain why.

Expert Witnesses Are Authoritative

The term “expert” is short for “subject matter expert” in the context of witness services. Generally speaking, an expert: 1) will have published extensively in their field over a long period of time, 2) will have practical experience relevant to the subject matter at hand, and 3) will have experience in court (or arbitration) cases that are similar to the instant dispute. The more experience an expert has, through some combination of practical experience, scholarship and trial experience, the more authoritative the expert will appear.

When it comes to cannabis litigation, I’ve worked on both state and federal court cases on everything from attorney malpractice allegations, to administrative rules and policy, to industry practices and market dynamics. I was first hired as an expert shortly after the 2018 Farm Bill passed, in a litigation where the ability of a hemp grower to obtain a bank account was a contested and critical question. I was able to point to articles I had written on the topic and I detailed my personal experience with credit union, government and industry clients to the court, under direct and cross-examination. The court found this testimony persuasive, and ruled in my client’s favor.

Expert Witnesses Can Leverage Settlement

Oregon is an interesting and unusual state, in that expert witness discovery is not permitted. We have “trial by ambush.” This means that a litigant is not required to disclose the content of an expert witness’ testimony in advance, that witness’ identity or even their existence. Absent mutual agreement between the parties, there are no expert witness depositions, interrogatories, or other discovery. Other states, like California, take a more traditional approach and govern expert witness discovery in their codes of civil procedure.

Regardless of the discovery setting, however, there are situations where a litigant will disclose its expert outside of the normal discovery process, or disclose key testimony that the expert will provide. This is often done to leverage a settlement or even a voluntary dismissal of an opponent’s claims. I’ve also had attorneys retain me as an expert witness at the outset of a matter, prior to anyone even filing a complaint or statement of claim. I was told by one experienced litigator she wanted me available (and unavailable to the opposition) regardless of litigation developments. This would “lock me up” and maximize her clients’ prospects of a favorable outcome down the line.

Expert Witnesses Can Offer Insight

People tend to think of expert witnesses as being most valuable to present compelling testimony. That’s not exactly right. Sometimes, an expert can provide critical insight to his or her clients well in advance of any testimony– or even discovery. And sometimes, those insights will greatly influence the client’s approach or strategy in the dispute. An expert can confirm a client’s line of thinking on a particular issue, for example, or the expert may introduce an idea or approach that had not been considered– and which has critical bearing on the client’s prospects for success.


There are so many cannabis business disputes going on around the country. Here in Oregon, complaints are filed with the courts almost weekly, and other disputes are filed in private arbitration. Many of these disputes turn on whether a course of action (or omission) by one party was reasonable, or negligent, or reckless, or whether it comported with administrative rules and policies in effect at a given time. Expert witnesses may also assist with other crucial questions, such as the value of a business in dispute. In many of these cases, engaging a qualified, capable expert witness can make all the difference.