The conclusion to our series on How to Be an Effective Expert Witness in Court.

The final function of an expert witness is to testify live at trial. This is the culmination of all the work that has gone on before. In many ways it is the most important thing an expert witness does. It is your chance to influence the judge and jury who will ultimately make the key decisions in the case leading to the final outcome. The reality is that the vast majority of cases settle before trial. Thus, even if you've been involved as an expert in many cases, it is likely you have limited experience testifying as an expert witness at trial. Nevertheless, all your work in a case must be premised on the possibility you will be called to testify at trial. You must be prepared to meet the challenges of trial testimony, and you must anticipate them as you go through the other steps discussed in the prior articles in this series. In many cases what you say and do at trial will make or break the case.

It is helpful to understand the overall process before discussing individual aspects in detail. The process begins with meetings with your attorney to prepare for your testimony. The number of meetings and the extent of preparation will vary depending on the importance of your testimony to the case overall. You will define the nature and scope of your testimony, discuss the exhibits you will utilize at trial, and determine how best to deliver the information the attorney wants you to convey to the jury. Typically you will rehearse your testimony and be subject to a mock cross examination. The goal is to prepare you to testify in such a way that no question will be asked of you at trial that you have not already considered and to which you have not already formulated an effective response. By the time you get to trial, if your attorney has done his or her job properly, there should be no surprises.

Once the day of trial arrives you will begin with direct examination. This is your opportunity to tell what you've done and what you know the way you and your attorney want to present the testimony. Direct examination involves responding to open ended questions from your attorney. The attorney will be limited in the way he or she can ask questions; leading questions will not be allowed (unless they try, and the other side fails to object). The norm is to limit your testimony to direct questions which require you to provide a narrative response. Leading questions, i.e., those requiring only a "yes" or "no" answer, are for the opposing attorney and should be encountered only during cross examination. One of the most important parts of trial preparation is the time spent educating you on how to deal with leading questions, and to help you anticipate how they will be used against you. If the attorney fails to raise the issue with you during trial preparation you should be sure to raise it on your own.

Direct examination is your opportunity to impress the jury with your qualifications. You will also want to demonstrate the thoroughness of your work so your testimony will be seen as authoritative and your ultimate opinions worthy of belief. You will frequently be called upon to do more than testify about what you have done. Often your primary role will be that of an educator, teaching the jury the technical subjects they need as a foundation for understanding your ultimate theories and opinions. It can be a challenge to explain highly technical subjects to a group of lay people. A common rule of thumb is to assume you are teaching a group of eighth graders in order for you to pitch your presentation to the right level of sophistication and to have the broadest impact on the majority of the jurors. You must never forget that technical expertise is useless if you cannot explain the concepts in simple enough terms that the jury understands them. By the time you finish direct testimony you should have demonstrated your competence, explained what you did in the case, educated the jury as needed, and offered your ultimate opinions on the subjects about which you are qualified to respond.

After direct testimony comes cross examination. This is the opportunity of the opposing attorney to attempt to undo everything you accomplished in direct examination. The rules allow the attorney the option of asking leading questions, and the normal practice is to make certain that every question in cross examination is a leading question. It gives the attorney the greatest likelihood of controlling and limiting the effectiveness of your response. It also gives the attorney a method of manipulating your testimony in an adverse way to the greatest extent possible. You should anticipate that you will be attacked wherever possible on your qualifications and expertise, on the methodology of your work, and on the reliability of your ultimate opinions. In other words, expect a direct challenge to everything you did on the case. As you respond you need to keep your cool, answer truthfully, and not attempt to argue with the questioning attorney. It's inevitable that your opponent will be able to score some points. Don't let that fact throw you. Finally, understand that to the extent you testify in a way that seems confusing or unhelpful to your case, your attorney will have another chance to ask questions to permit you to clarify or modify the responses you made during cross examination.

Sometimes a more subtle approach is used by the cross examining attorney. Rather than challenge you they may try to use you as their own expert witness to help prove points that benefit their side of the case. This is particularly true when they haven't designated a counter expert. They can use your expertise and answers to establish other points or opinions that have not been raised by your attorney. If this occurs there is not much you can do besides answering the questions truthfully to the best of your knowledge. If there are concerns about what you say in this regard it is the obligation of your attorney to deal with them on redirect examination. Needless to say, this is a possibility that should be anticipated by your attorney and discussed during your trial preparation.

After you have completed cross examination, your attorney will be given another chance to ask questions. The purpose of this redirect examination is to address any questions or concerns that arose during your cross examination. It is not intended to be a rehash of your direct examination, nor will you be permitted to go into a totally new line of testimony unless it rebuts something that was raised by cross examination. Redirect is intended to be an opportunity for you to clarify or correct the responses offered in cross examination to remove any doubt or misinterpretation caused by the opposing attorney's questions.

Qualifying as an Expert for Trial
As discussed in a prior article, if you are in federal court you will need to meet a Daubert challenge before you will be permitted to testify. State courts vary on whether they apply the Daubert standard or some other standard to qualify as an expert. Typically this challenge will occur prior to trial, though it is possible that it will occur during trial with testimony being taken outside the presence of the jury before you are allowed to testify. You will not be allowed to testify as an expert unless the judge determines you have the requisite education and expertise, and the work you have done is sufficiently reliable to meet the standards set forth under the applicable evidentiary rules. Once you are established as an expert it will be up to the jury to determine how much weight they wish to give to your testimony.

Even though this determination is typically made prior to trial, you will still be required to demonstrate your expertise in front of the jury. Sometimes opposing counsel will attempt to short circuit the process of establishing your credentials by offering to stipulate to your expertise. Few attorneys will accept such a stipulation. They want the opportunity to explore your CV in front of the jury to establish that you are a reliable and trustworthy witness. Understand that formal education is one way to develop expertise, but practical experience acquired through exposure in the work place or through other life experiences may serve as a perfectly viable way to develop expertise as well.

Opinions "To a Reasonable Degree of Probability"
One of the things an expert witness may do at trial that a lay witness may not is offer ultimate opinions. This means an expert is allowed to consider various pieces of evidence and draw conclusions from them as seen through the lens of the expert's specialized knowledge and training. An expert will not be allowed to speculate, and ultimate opinions cannot be based on a mere possibility that something is the case. The opinions must typically be offered "to a reasonable degree of probability" within the expert's field of knowledge. While it is possible the sufficient testimony will be offered that it is already clear the expert's opinions meet this standard, it is typical for your attorney to use the buzz words "to a reasonable degree of probability" when asking you to identify and state your opinions. Normally they will ask a conclusory question as follows: "Do you have an opinion to a reasonable degree of probability in your field of expertise that (insert your ultimate opinion)…," or "Are all the opinions you have offered today given to a reasonable degree of probability within the area of your expertise?" You should not be caught off guard on the witness stand or be confused by a question using this phrase when your attorney is asking you to state your ultimate opinions. I've seen expert witnesses fall apart on the stand because they have no idea what this means and they fail to testify that everything they've just said does in fact meet this standard—even when it does. This is something that should be discussed during trial preparation, and if your attorney fails to discuss the topic with you, you should raise it. You want to be certain you understand the standard to which you must testify, and know how to properly formulate your statement of ultimate opinions at trial.

Handling Direct Examination
As indicated above, it is expected that you will have discussed all the questions your attorney will ask you in direct examination as part of your preparation. Sometimes, however, your attorney may ask you a question that sounds new or different. If that happens, first make sure you understand the question. If you don't, indicate that fact and ask the attorney to rephrase. You should never have to guess what you are being asked. Try to answer the question thoroughly, but without volunteering additional information that is not required to answer the question. Don't give the other side ammunition to use against you. You should know going into trial just how much information you should give to a given question.

One issue you should determine in advance is whether your attorney wants you to make eye contact with the jury. I personally never like a witness that spends all his time looking at the jury when answering questions. Some witnesses think they can establish a rapport with the jury this way. I think it is grandstanding. Normally you are engaged in a dialogue with the attorney and your focus should be on the attorney asking questions. Some limited eye contact with the jury is appropriate, but you are not there to become buddies with the jury. This comment reflects my own bias, and I suppose there are attorneys who disagree with me. In any event, you should ask your attorney during preparation how much eye contact they want you to have with the jury. How to dress and how to comport yourself are also topics to be discussed in advance.

Another thing you should avoid is inappropriate jokes or comments. You are not an entertainer—you are an expert witness. Some levity may be appropriate, but the lead should come from the attorney, not from you. Finally, don't be a windbag or be pompous. Nothing turns off a juror's hearing faster than testimony from a witness using inflated vocabulary or from someone who has an inflated sense of self. Remember your job is to communicate specialized knowledge to a group of average Joes. You are to educate, not pontificate. You certainly shouldn't be falsely humble, but you don't need to be a braggart to be believed by the jury.

Handling Cross Examination
When being cross examined you should always be aware that the opposing attorney is your enemy no matter how much honey drips from the questions he or she asks. Don't answer a question you do not understand. If you don't understand make them restate or rephrase the question. Don't help them ask the questions by offering to clarify their malformed questions. Keep your answers as short as possible while still being responsive. Don't guess. If you don't know or don't recall, they may be able to refresh your memory with additional evidence. If you guess and give the wrong answer that evidence may come in through a different witness and be used in closing argument to make you look foolish and unbelievable. Don't be argumentative. Your primary work will be done in direct examination, and any challenges to what you've said that arise during cross examination will be taken care of by your attorney in redirect examination.

Working With Exhibits and Demonstrative Evidence
One final topic deserves consideration, and that is the role of the expert witness in developing exhibits and demonstrative evidence to be used at trial. While exhibits are generally left up to the attorney, and the expert merely works with what the attorney has deemed worth presenting to the jury, participation by the expert in helping the attorney create exhibits early enough before trial to give sufficient time to prepare them well is desirable. Often times the expert is more familiar with the tools that were used to collect and analyze the data that serves as the basis for the expert's ultimate opinions, and the expert can offer suggestions on how to present such evidence in a way that will educate and engage the jury. It is particularly useful when you are presenting dry technical evidence to have something tangible to pass to the jury to keep them awake and engaged.

For example, most people have no idea what a hard drive is or how it works. They just know it is part of a computer. Taking an old computer into court, removing the cover, and then showing how the hard drive is removed for imaging can help demystify the process of collecting electronic data. Demonstrating how a Hardcopy III was used to create the hard drive image that was analyzed can help establish a favorable impression of the expert's collection activities. Opening up a sample hard drive to show the internal components will help orient the jury when the testimony turns to understanding bytes, sectors, and clusters of data. Graphics used with trial presentation technology can be used to explain things like slack space on the hard drive, or how a deleted file can be recovered. Turning to the results of the analysis, it might be helpful to present a few screen captures of a typical screen the analyst views when reviewing the data. It helps explain the process and shows you are using legitimate tools for your analysis. Finally, screen captures can be used to demonstrate the ultimate results of the examination to help fix in the jury's mind that there is objective evidence underlying the expert's ultimate opinions. Screen captures should be used judiciously, but showing a select few to the jury will help them understand the vast amounts of data the expert has sifted through, and how the process of isolating the relevant evidence was completed.

Conclusion
With the explanations and suggestions contained in this article and the others in the series you should have received a basic education on the role of an expert witness in litigation. Hopefully, you've been given ideas that you can discuss with the attorneys who hire you to make sure you are as effective as possible. Trial attorneys must juggle a great deal of information of varying types when preparing and presenting a case to a jury. Having a proactive relationship with the expert, where the expert is able to offer helpful suggestions to the attorney is a great advantage. Don't be afraid to make suggestions to the attorneys you work for. After all, the worst they can do is say no. More likely you'll help them think of ways to present information to the jury that is more effective than they would have come up with on their own. Finally, keeping in mind the ultimate experience of testifying at trial throughout all phases of your work will help you be a more effective witness and a more valuable part of the attorney's team.

Bruce A. Olson is an experienced board certified civil trial attorney and a CCE who has testified at both depositions and in court as a computer forensic expert.

Read past articles from our series on testifying as a digital forensic expert witness: Part 1 looked at the role of the computer forensic expert; Part 2 at expert qualifications and preparing a CV; Part 3 examined the Daubert rules for qualification; Part 4 explained the new federal rules of civil procedure; Part 5 discussed the preparation of an expert report; and Part 6 outlined preparing for and testifying at depositions.