Writing an Expert Witness Report

Joseph O'Neill

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— Updated on May 3, 2022

Writing an Expert Witness Report

As a new expert witness, one of the most confusing – and important – elements of your expert witness testimony will be your expert witness report. A good attorney will work with you every step of the way to ensure that your impact on the case is as substantial as possible. However, it’s also important to do your own homework. We’ve caught up with a few top litigators, trial consultants, and experts who’ve shared their best advice for honing your expert witness report into a compelling, and convincing, piece of evidence.

Expert Report Gerald M. FisherAs a trial lawyer handling complex cases, I use experts frequently. The major criticism I have with most expert witness reports I’ve seen, and therefore my most important tip, is with respect to experts’ inability to state a conclusion succinctly and clearly up front, and to follow it with a succinct statement as to their reasons for that conclusion. That provides clarity. The detail that follows provides credibility to the clear, succinct statement.

Other common expert mistakes are:

1. Attempting to tell me what they think I want to hear. This presents two problems. First, if the expert truly is one, I need to know what reality is. I can decide whether the report should be used as evidence. Often, by telling me the “bad news,” I can best decide how to handle the matter early on. I can also handle it in a manner that is in the client’s best interest. Rather than waiting for the expert to get hammered on the witness stand or in deposition. Second, it presents me with the problem of lacking confidence in my expert witness and determining whether I should rely on that person.

2. Not giving me practical advice when there is a practical solution to a problem of which they are aware because of their expertise.

3. As noted above, reports that are not clear in their conclusions and the basis for their opinions.

Gerald M. FisherFreeman, Freeman & Smiley, LLP


Expert Report Randy H. McMurray A good expert witness report should be clear and precise about the opinions and conclusions of the expert, as well as the basis for each conclusion reached by the writer in the report. The most common mistake I see in expert report writing are opinions that are not supported by substantial evidence which are subject to attack at deposition and trial. The expert must be fully prepared before preparing the report. The failure to contact the retaining attorney regarding any concerns before completing the report can result in the loss of the case. This is because major issues are not addressed or prepared for.

Randy H. McMurrayMcMurray Henriks, LLP


Expert Report David P. Beeson The report needs to be thorough, complete and needs to address the issue(s) presented.

An expert report writer must keep in mind that the report is NOT the starting point for discussion. Rather it is the finish line. Many experts, in numerous disciplines, treat their report as the beginning of the discussion. When additional opinions are later added, impeachment of the conclusions reached in the original report becomes very easy. Plus, in cases where multiple disciplines are used such as life care planner, economist, vocational rehabilitation coach, and orthopedist, communication between the experts and coordination and cohesiveness of opinions is paramount. The experts need to talk to one another during the formation stage. Then they need to be able to build their reports on the shoulders of the other team members. Lack of communication between experts often results in inconsistent, and easily attacked, opinions. Plus the damage done by later adding or changing opinions and conclusions is self-evident.

David P. BeesonDavid P. Beeson & Associates 


Expert Report Douglas G. Wah Keep it simple. We know the expert has the skill, the knowledge, and the expertise to be called an expert. When it comes time for the expert to write his or her report, they need to be able to communicate that expertise to an audience of laypeople. The expert needs to write it in a manner that if parts are read to a jury, they will have no problem following its meaning. Write it so that it can be explained simply. The most common mistake is the failure to do so.

Too many experts think it is important to sound intelligent and impress the reader with their knowledge. In doing that, they “assume” the reader has the same level of knowledge to as they do, that the reader already knows what is being written about. Usually, the reader does not have such skill. I try to keep everything at a level at which various members of my support staff can understand it.

Douglas G. WahFoley & Mansfield


Expert report Stephen Allen JamiesonIn order to write a successful and persuasive expert witness report, the expert must know the facts of the case. They need be to be able to recite them accurately, or else not at all. An expert who does not fully know the details of the case at hand is vulnerable to the number one area for effective cross examination. It doesn’t matter how qualified the expert is, how impressive their qualifications are, or how skilled they are in deposition or testimony. If the facts they rely on are inaccurate, their “expert” opinion is worthless. Their credibility is blown beyond the point of recovery.

Stephen Allen JamiesonSolomon, Saltsman & Jamieson


Expert Report Farrah ParkerWhile it’s important to focus on your own professional opinion, the report must assist in dismantling the opposing assessment. Include statements that show the comprehensive nature of your work by including a few facts for why the opposite view cannot be true. Close with going back to yet another powerful piece of information proving your opinion.

Also, it’s tempting to create a report that is full of industry lingo, whether medical or financial. But you should be careful to avoid too much jargon in your report. Be sure to write for your audience and break down phrases that may detract the reader’s focus away from your point. In no way should you diminish the key terms. However, be sure that you surround them with supplemental information that helps the jury digest it.

Farrah Parker, M.A. – F.D. Parker and Associates


Include a “Mini-CV” on the first page of your expert witness report. This will help you establish your credentials and give the reader some background as to why your experience is relevant for this case.  You should also articulate the bases of your expert findings and opinions, as well as the scope of overall future testimony based on the same. Never opine on credibility of witnesses (and in my line of work – children’s credibility) or the ultimate issue [at hand in the case] (Rule 704).

Dean Tong, MSc., CFCForensic Trial Expert


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