When you depose an adverse expert, you should always serve a subpoena duces tecum.
- By Leonard Bucklin

First reason to always serve a subpoena duces tecum: even if you have served the adverse party with a Request for Production of the Adverse Expert's Files on the adverse party, it is surprising how many times "something extra" turns up in the expert's files if you subpoena the expert to his/her deposition. Sometimes, the other side was in no hurry to ask their expert to send them more items to send on to you.  Sometimes, it's because the dignity of a subpoena versus a letter request from an employing attorney jars more loose for you. So always serve the expert with a solid subpoena duces tecum.

LawyerTrialForms' has a form for you to create
"The 21st Century, Advanced Strength, Subpoena Duces Tecum".

Second reason:  a witness is not obligated to attend a deposition -- or bring anything --- unless he/she has been summoned by a valid subpoena, properly served under the rules of the court involved. Absent a valid deposition subpoena, properly served, the witness may ignore you with impunity.

♫ (That's a WARNING chime.) All too often an attorney noticing a deposition in one state for a case venued in another state (e.g., deposition in Arizona of the witness, to be used in a Texas lawsuit) mails the expert a subpoena issued by the court of the state of venue.  Except for a few unusual times when the law of both states involved permits it, a subpoena out of one state is not valid in another state. Be sure your subpoena is properly issued, from the proper court. If you as an attorney serve a document that looks like a subpoena, but is not a valid subpoena, or is not properly served, you may be open to a charge of abuse of process.

When you want an unfriendly witnesses to attend her deposition, it’s obvious: you need to serve the subpoena to insure her attendance at the deposition and to bring what you want brought. If the witness has been duly summoned to a deposition but fails to attend, then the court may issue an “attachment of the body” or “bench warrant” (local terms vary) directing the sheriff or marshal to arrest the witness and deliver the witness to the deposition. Alternatively, you can use a more difficult process to have the court fine or jail the witness for contempt of court.

It is possible to claim that the adverse expert is "under the control" of the adverse party and so the adverse party is able to produce the witness --- if the court so orders.  The logic is that service of a notice of taking the deposition of the adverse expert should compel your adversary to produce their own expert at the noticed time and place. That’s a logical legal theory, but (1) not all courts agree, and (2) if adverse counsel wants to argue about it, you may have to get a court order to compel the adverse party to use its control to produce the expert.

Here is a sample case you might want to use as one entry to your research on the subject.

“....we are compelled to agree with petitioner to the extent that an Alabama trial court does not have jurisdiction over a non-party out-of-state witness....We, therefore, cannot hold that Judge Mullins had jurisdiction to force Dr. Morton [an expert residing in Georgia] to submit to a deposition in Jefferson County, Alabama. However, our review of the record reveals that Judge Mullins ... [ordered the plaintiff to] make his expert witness available for deposition in Jefferson County. This is what the judge ordered. He has the power to do so under his general power to control his court and his trial docket. The order is to the party whose presence he has. Let us be mindful of the fact that this is not a fact witness, as such, but an opinion witness, presumably paid with the plaintiff's funds. We are not to be interpreted as holding that all out-of-state expert opinion witnesses can be required to come to Alabama. But the judge, in the exercise of his discretion, may order a party to produce the witness .... And he has under Rule 37(b)(2), as well as under Rule 26(b)(4)(A)(I), Ala.R.Civ.P., a plethora of options available to be used as sanctions at his discretion if the petitioner does not comply with his order. His choice of sanctions will not be set aside except in the case of clear abuse.
                - Ex parte Leverton, 536 So. 2d 41 (Ala.1988).

But --- absent a court order directing the adverse party to produce their expert, even with an agreement by counsel that she will produce her expert witness for your deposition, some judges will take the position that it is your obligation as the person noticing the deposition to subpoena every witness that is not the adverse party. In spite of employment or other financial control the adverse party might have over a witness, some judges will side with an adverse party that says an individual cannot be brought by force, all they can do is request that he/she please go to a deposition.

So, with both friendly and unfriendly witnesses, if opposing counsel have traveled to take the deposition and finds an empty chair, you may be liable for the other side’s costs including the attorney’s fee. The federal rule on the subject is typical of state rules.

If the party giving the notice of the taking of a deposition of a witness fails to serve a subpoena upon the witness and the witness because of such failure does not attend, and if another party attends in person or by attorney because that party expects the deposition of that witness to be taken, the court may order the party giving the notice to pay to such other party the reasonable expenses incurred by that party and that party's attorney in attending, including reasonable attorney's fees.
             Fed. R. Civ. P., 30(g)(2)

Hence the rule you should always follow: no matter how many assurances you get that an expert will appear at a deposition, serve every expert witness (both your own and the adverse party's expert) with a valid subpoena, and serve it according to the jurisdiction’s rules for personal service.

There is available a complimentary article on the Federal Rule versus state rule
differences on protection of communications between attorney and expert.

All The Best,
 
Leonard Bucklin
Attorney at Law

P.S. The LawyerTrialForms™ form for you to create your "21st Century, Advanced Strength, Subpoena Duces Tecum" is available here