(Editor’s note: This is an edited excerpt from an article written by John P. Paone Jr. and John P. Paone III that ran in the latest edition of New Jersey Family Lawyer, a publication of the NJSBA’s Family Law section. Members can read the full issue here.)
If you engage in complex matrimonial litigation, you will need to know how to cross-examine expert witnesses. The ability of family law practitioners to cross-examine experts effectively is not simply a matter of trial skill. While trial skill is needed, a large part of being able to successfully confront an expert is the result of extensive pretrial preparation.
Step 1: Assessing the Potential for Expert Involvement
Identify any issues which may require involvement of experts. There are many areas of family law which may require experts, including health care professionals who render opinions on parenting time and child custody; forensic accountants who determine the cash flow and fair value of a business; occupational experts who assess the potential employability of a party and opine on that party’s ability to earn; medical experts who determine whether a party is disabled and cannot be employed for health reasons; and a vast array of appraisers who may value real estate, pensions, jewelry, artwork, wine, coins, stamps, guns, sports memorabilia, antique furniture, exotic vehicles, boats, planes, and a whole host of marital property.
Step 2: Use Your Discovery Tools
There is no excuse for being caught off guard by the testimony of an expert witness. The rules of discovery provide ample avenues to identify experts and to familiarize yourself with their opinions. Interrogatories are essential to finding out whether the adverse party has retained an expert and whether that expert may be called as a witness at trial.
Step 3: Know the Type of Expert You Will be Confronting
Will you be confronting a single joint expert, the court’s expert, or the expert retained by the adverse party? In many cases, the expert is either selected jointly by the parties or appointed by the court. The benefits of having a common expert include reducing fees, since the parties will likely share the cost of the joint or court expert rather than spending money on two experts to address the same issues.
Step 4: Investigating the Expert’s Curriculum Vitae
Does the expert possess the appropriate credentials that qualify them to render an opinion on the issue in dispute? Even assuming the expert possesses the requisite qualifications and credentials to testify, counsel must question whether it is appropriate for the expert to do so.
Step 5: Hiring a Consulting Expert
Consider hiring a consulting expert to review, critique, and discuss the adverse expert’s report. Consulting experts can assist you in understanding both the subject matter and the significance of the opinions offered by the adverse expert. The consulting expert will be able to point out weaknesses in the adverse expert’s report and assist you with preparing effective cross-examination questions at trial.
Step 6: Determining Whether an Expert is Truly an Expert
To determine whether the adverse expert is indeed an expert, the Rules of Evidence require that the opinions must be based on “scientific, technical, or other specialized knowledge” which will assist the trier of fact in understanding the evidence or deciding a fact in consequence. It is important to remember that trial judges are responsible to act as gatekeepers for the purpose of excluding unreliable expert testimony. This typically involves an analysis by the trial court as to whether the expert’s theory or technique has been tested objectively.
Step 7: Exploring What is Behind the Expert’s Report
Cross-examination of an expert is often a crucial element in determining the accuracy, reliability, and probative value of the expert’s findings and opinions. To determine the credibility, weight, and probative value of an expert’s opinion, the practitioner must question the facts and reasoning on which it is based. What has the expert relied upon and where did they get the facts and data in order to render their opinion?
Step 8: To Depose, or Not to Depose, That is the Question
Upon receiving the expert’s report, consideration must be given as to whether it is prudent strategy to depose the adverse expert before trial. If the expert is deposed, will that assist in locking in their testimony at trial and obtaining concessions on important points? Or, will proceeding with a deposition tip off the adverse expert to your trial strategy and questions that may have otherwise been posed for the first time during cross-examination at trial?
Step 9: Impeaching the Expert
After all relevant documentation and information about the adverse expert has been obtained during discovery, the practitioner must then decide how to best use it at trial. An effective cross-examination of the adverse expert will present a theme to the trial judge as to why the expert’s opinion is not credible and should not be relied upon.
Step 10: Keep it Simple and Short
It is unlikely that you will completely “destroy” the adverse expert at trial. Experts are smart and will have far more experience in a particular subject matter than the trial attorney. It is imperative that counsel follow the cardinal rule of cross-examination and only ask leading questions requiring yes or no responses. When cross-examining experts, focus on the area where the opinion is most vulnerable. Establish your point, and then move on. In addition to boring the judge, a long cross-examination risks allowing the expert to rehabilitate themself by explaining away any inconsistencies and reconciling any areas of weakness in their testimony and report.