By far, one of the most significant advantages to hot tubbing is its efficient approach to presenting expert testimony. Because the experts are able to identify topics on which they agree and disagree early in the process, they can then focus their presentations and discussions on the topics that are actually at issue.  This organization alone in turn reduces the overall time spent on presentation and cross-examination.  In fact, in one of the first Australian cases in which expert evidence was presented concurrently, a hearing that was estimated to last six months was shortened to just five weeks thanks in part to the use of hot tubbing.  Such a reduction in hearing time should translate directly to a reduction in costs.


The hot tubbing process is also useful in situations where putting an expert through a traditional direct, cross, and redirect process would be time-consuming and costly.  In the all too common situation where multiple experts testify over the course of several days or weeks, the trier of fact must try to recall previous experts’ statements and how they compare to the current expert’s positions.  Needless to say, this task is difficult and may lead to confusion or the acceptance of the most recently presented testimony. Where concurrent expert testimony takes place, however, the arbitrator or mediator has the benefit of immediately hearing the differences in the experts’ opinions and can pursue a topic further should he or she choose.


Hot tubbing also reduces the amount of information presented, meaning the trier of fact has less to decipher when reaching a decision.  Concurrent expert testimony not only reduces the duration of the hearing as a whole, but it also reduces the amount of information that must be remembered at any given time.  As a result, the mediator or arbitrator can make more direct comparisons between the positions staked out by the experts, which enhances their overall ability to rationally analyze each party’s argument.  Moreover, by cutting away superfluous technical and scientific testimony about undisputed topics, the arbitrator or mediator may spend more time focusing on the actual disputes in the case rather than wading through very complex and technical material that is often unnecessary for the fact-finder to know or understand.


Importantly, hot tubbing helps to decrease any bias present in expert testimony as it promotes an informal and open discussion that generally is less adversarial than the conventional approach.  It also may even help reduce an expert’s willingness to jump to unreasonable conclusions or be outright dishonest because the expert is testifying with others in his or her own peer group, meaning the expert’s opinion could be challenged at any point during the process.  At the very least, having experts testify with others of equal status and stature is likely to lessen instances of embellishment, avoidance of tough issues, and harsh rhetoric.  This benefit may prove to be particularly useful should attorneys wish to reduce overall hostility in an already contentious matter.

Additionally, the experts address the topics in their own words, often not relying on the attorney’s skills in direct or cross-examination to arrive at the relevant information. The perception that the expert is delivering his or her own opinions almost certainly will help bolster the expert’s credibility. Furthermore, the expert is made to feel more like an independent and impartial third party under this arrangement.


Hot tubbing may also prove especially effective when conveying scientific or statistical information because it enables the fact-finder to observe a public peer review by other experts also concurrently testifying.  It allows the arbitrator or mediator to understand the methodologies and analyses that the experts undertook to arrive at their conclusions.  Also, because the trier of fact has the opportunity to ask their own questions, the arbitrator or mediator would have even more opportunities to enhance their understanding by participating in the discussion that unfolds before them.


Finally, the actual physical placement of the experts themselves helps to affirm a perception that the experts are neutral information-providers rather than party-hired advocates.  Because experts typically sit side-by-side during the hot tubbing process, the adversarial relationship between the parties is downplayed significantly.  As one Australian court noted, “There is . . . symbolic and practical importance in removing the experts from their position in the camp of the party who called them.”  Not only does this placement help increase the credibility of the experts before the arbitrator or mediator, it also places the experts on an even footing in order to prevent one expert’s opinion from appearing dominant solely because that expert is more at ease presenting his or her testimony in an adversarial setting.




Of course, hot tubbing is not without its disadvantages. One issue with concurrent expert testimony is that the more experienced, confident, or assertive experts will likely dominate the procedure and, therefore, will more likely appeal to the fact-finder.  More so, when experts are not well-matched and have differing levels of credentials or experience, those experts with superior qualifications may prevail despite the inferiority of their opinions.


There also exists the possibility that attorneys will coach their experts on how to respond to questions based on the opinions of the other party’s expert.  Although this disadvantage exists in conventional expert testimony practices, one of the purposes of hot tubbing is to eliminate biased and preconceived answers in favor of natural and flowing conversation among multiple experts.  If this in fact does occur, it similarly leaves the tribunal in a position where it must decide the merits of the case in the face of a deadlock between the opposing party experts.


Another natural issue with concurrent expert opinion is that without the direction of a skilled moderator, the hot tubbing process will be almost entirely useless. In one scenario, the concurrent testimony may devolve into nothing more than a squabble between the parties.  In another scenario, the experts may simply fail to engage one another and the moderator may fail to intervene, meaning the lawyers revert to the traditional direct and cross-examination styles to elicit answers from the witnesses.  In yet another scenario, while the experts may get along and readily converse, they may do so at such a high-level that only those trained in the field will be able to understand.


Arbitrators, mediators, and lawyers also have concern as to how their roles might change if hot tubbing were incorporated more regularly into proceedings. Arbitrators and mediators may resist implementing hot tubbing practices because such a procedure would place additional managerial burdens on them.  Alternatively, attorneys often worry that hot tubbing will remove their control of witness examination, thereby disrupting their planned trial strategies.  Because attorneys typically will not be present at the “meet and confer” stage of hot tubbing, attorneys may worry that their expert will stipulate to a seemingly innocuous and unimportant fact that later proves to have a negative impact on the case.  As such, many of the key participants in the hot tubbing process may simply find the process to be too radical to suit their interests.


Also, some practitioners argue that hot tubbing is simply not conducive to document-intensive cases.  The conversational nature of concurrent expert testimony may not be well-suited to expert testimony focused on particular documents, especially when there are voluminous documents that require expert analysis.  It also may be very risky to call the tribunal’s attention to large numbers of documents without being prompted to do so.  At the very least, having a panel of experts discuss each portion of a number of documents ad nauseam may not be the most efficient use of precious hearing time.


Best Practices For Implementing Hot Tubbing


One of the fundamental aspects that will determine whether hot tubbing is successful is the tribunal’s ability to facilitate and control the proceeding.  This means that the arbitrator or mediator is well-prepared and familiar with the issues being discussed by the experts so that they can better guide discussion.  Thus, as moderator of the session, the arbitrator or mediator must ensure that controversies at issue are identified and discussed, which likely entails significant preparation and planning on their part.  Moreover, the arbitrator or moderator will help set the tone of the process and must actively work to prevent the hot tubbing session from taking on derogatory or otherwise negative and combative tones.


The expert must also have a number of critical traits due to the fact that the attorney will not be guiding the whole of the expert’s testimony via direct and cross examinations.  First and foremost, the expert must be able to convey his or her ideas in simple terms using easy-to-follow examples.  The expert should be able to communicate his or her ideas in a way that is not condescending and clarifies what typically amounts to highly technical or scientific processes.


Second, the expert must possess the ability to question other experts during the hot tubbing process to effectively underline any areas of error or inconsistency.  The expert, however, must be able to conduct this line of questioning without appearing too antagonistic or hostile. Accordingly, it is important that experts have the same level of expertise so that no expert feels that he or she is more qualified to discuss a particular topic and appears condescending or patronizing toward other experts.  Additionally, an expert also should be a good listener and make use of the information the other experts present during the hot tubbing session. Provided that the hot tubbing process is a collaborative process, the expert should be able to build off the information provided by others to enhance his or her own argument.


Finally, the expert must be aware of the overall message his or her party is attempting to convey and ensure that he or she stays on message during the hot tubbing session.  This of course means that the expert will know the nuances of the case and understand what facts and issues may potentially impact their client.  The expert, therefore, must always be mindful of their client’s position and seek to participate in the hot tubbing session in a way that serves to support their client’s position in the matter.



Reprinted with the permission of AACE International, 1265 Suncrest Towne Centre Dr., Morgantown, WV 26505 USA. Phone 304-296-8444.



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