Being an expert witness requires knowledge, skills, education, experience, and training. Thus, expert witnesses are not always available in the exact location an attorney needs them to be. As a result, attorneys are often forced to hire out-of-state expert witnesses. But, many attorneys are unsure how to compensate such an expert witness for travel expenses.Generally, the topic of expert witness compensation is a sensitive topic and rarely discussed. There do exist a number of guidelines issued by various professional organizations to which experts belong, but often these are completely voluntary standards. The standards usually are little more specific than what the expert should bill ethically and in a manner that does not jeopardize his or her ability to remain objective, such as having a stake in the outcome of the case. Indeed, many experts are, themselves, reluctant to discuss compensation for what are, perhaps, obvious reasons.Nevertheless, when it comes to the question of travel expenses, there are four generally accepted ways that experts' travel fees can be paid:1. Same as Normal Hourly Rate. This rate makes sense from the view that the expert's time is being used by the particular matter for which he or she is traveling, making it impossible for the expert to work on other matters at the same time. As a result, the expert should be able to charge the normal hourly rate for expert services, because otherwise the expert suffers the loss of income that time represents.For the attorney, one way to deal with this expense is to ask the expert to make productive use of the transit time. For example, the expert could be asked to review records pertaining to the case while on a plane, write the expert witness report while waiting to board, or outline areas of inquiry for the attorney while stopping to eat.2. Discounted Hourly Rate. This is something of a hybrid approach that recognizes the expert's opportunity costs associated with travel time, but also recognizes that travel time is not entirely productive for the client, either. The expert charges the client a reduced hourly rate while traveling (often 50% of the normal rate).However, this approach also gives the attorney less leverage in demanding that the expert remain productive during travel time. For the expert, this can mean the opportunity for double billing (i.e., billing one client for actual work done on their case while charging another client for travel time). For the attorney and client, this can mean a greatly reduced fee.3. Fixed Travel Fee. As the name implies, this approach equates to an agreed upon flat fee for travel time. For example, the expert and the attorney/client may agree to a flat fee of $500 for the expert's time, round trip, plus the cost of the plane ticket. This gives the expert the freedom to work on other matters while traveling and gives the attorney and client the comfort of knowing exactly what the travel time will cost before asking the expert to make a visit. However, travel delays and other unexpected events can make such an arrangement much less workable for the expert. For example, if the expert's normal hourly rate is $200/hour, but he/she has agreed to a $500 travel fee, a canceled flight or other delay could leave the expert losing $1,600 a day, particularly if it occurs after the trial when the expert cannot do any additional work for the attorney/client. Nevertheless, under most circumstances, and barring the unforeseen, this can be a very fair arrangement well within the confines of the ethical guidelines for fair billing.4. No Charge for Travel Except Costs. Yet another approach is to simply ask the attorney and client to reimburse the expert witness for travel expenses, and not bill for time in transit. Again, this allows the expert to do whatever he/she wishes while traveling, and may be a good option for the expert who wishes to mix business with pleasure, spending extra time at the destination to take in the local scenery, visit family, or see a show. Similarly, for an expert who can work on the road, this may be one of the most fair and ethical ways to bill, given the expert can work on whatever matter he/she chooses and bill the appropriate client for that time. Nevertheless, this also means the expert's compensation for the time spent traveling is not assured, so it could also lead to an expensive travel delay if the expert runs out of work that can be done remotely.Obviously, other strategies could be employed if negotiated between the parties and still in line with the ethical requirements for both the attorney and the expert's professional organizations. It is in the interest of both attorneys and experts to negotiate an appropriate method of compensation for the expert's travel time. Of course, an expert's willingness to negotiate on such matters could be a reason to check with other experts to see if a more reasonable deal is available from an equally qualified expert.