In The Attorney-Expert Relationship: Unraveling the Complexity, Peter T. Tomaras writes on his experience as a premises liability expert witness:
In my view, attorneys should retain experts not merely to ratify their arguments, but for all the experience based information we can contribute. For instance, experts can support discovery by suggesting witnesses to interview and questions to ask. Most civil cases in my area of expertise–the hospitality industry–turn on the duty of reasonable care in the circumstances. Especially in cases lacking forensic, medical, or scientific aspects, my expert testimony may be pivotal.
Accordingly, I feel obliged to research every source that may help me formulate supportable opinions on each assertion in the complaint. My input should identify what the attorney’s client has done right, and also what the client might have done differently. Ultimately, counsel is preparing for deposition and trial, where the opposition will certainly explore potential vulnerabilities in my opinions.
As for a retainer and an engagement agreement, I have learned to require both, including a clause about who will pay for expert services, and who guarantees payment–something attorneys rarely bring up. Because financial considerations sometimes may limit the extent of investigation attorneys (or their clients) want from experts, the engagement contract can be adapted to each situation.