Code of Civil Procedure (CCP): Exchanging Expert Witness Information in California

CCP 2034 lays out how to calculate deadlines, which information must be exchanged, and in what fashion. As such, it provides specific guidance to parties in California state courts regarding several aspects of the expert witness process. As such, it provides specific guidance to parties in California state courts regarding several aspects of the expert witness process under Code of Civil Procedure 2034.010 and subsequent sections.

Rules for exchanging expert witness information appear in CCP 2034.010 to 2034.730. Key points from these sections include:

Timing and Deadlines

The trial date affects the timing and deadlines that apply to exchanges of expert witness information in California. According to CCP 2034.230(b), expert witness data must be exchanged “no later than 50 days before the initial trial date, or 20 days after service of the demand, whichever is closer to the trial date.” The court may choose to order an earlier or later exchange date depending on the circumstances of the particular case.

The date on which the trial date is set affects the service of a demand. Generally speaking, parties have 10 days after the initial trial date is set or 70 days before the date of trial to demand an exchange of expert witness information, whichever is closer to the trial date itself.

Thus, the process of demand and exchange follows this basic pattern:

Trial Date is Set

• 10 days later: service of demand deadline, OR
• 70 days before trial: service of demand deadline (whichever is closer to trial date).

Demands are Served

• 20 days later: information exchange deadline, OR
• 50 days before trial: information exchange deadline (whichever is closer to trial date).

When a deadline falls on a weekend or a court holiday, it moves to the next court day closest to the trial date. For instance, if the deadline falls on a Saturday, it moves to the following Monday (or Tuesday if the Monday is a court holiday). Under CCP section 2034, these adjustments ensure compliance with procedural rules while accommodating non-business days.

If a need arises to demand the exchange of additional information but the deadlines have already passed, lawyers may still motion for exchange. However, this motion must show “good cause” for the additional exchange.

Demand for Expert Witness Information Exchange

Information exchanges are typically based on a written demand each party makes to the other. Under CCP section 2034.230, the written demand must contain:

• The name of the client or party on whose behalf the demand is made
• A statement that the document constitutes a written demand
• The deadline the party has calculated for the exchange of expert witness information, including witness less, declarations, and other documents asked for in the demand

A copy of the demand should be served on all parties to the lawsuit, even if the demand is aimed at only one party. Generally speaking, personal or delivery service to a party or their attorney is deemed acceptable. A proof of service, completed by the serving attorney, should accompany each copy of the demand.

Preparing Expert Witness Information for Exchange

Once they receive a demand, a party or their attorney will typically respond by gathering the information they need to respond to the demand.

California courts are currently divided on how to designate retained versus non-retained experts, impacting the procedures involved in expert witness disclosures in California. At a minimum, however, the names and addresses of every expert whose opinion may be offered into evidence should be listed, unless a specific exception applies.

In addition to designating every expert witness the party or their attorney may seek to use, the exchanged information must also contain declarations from each witness where required. A declaration typically consists of:

• A brief statement of the expert’s qualifications
• A summary of the substance of the testimony the expert is expected to give
• A representation that the expert agrees to testify at trial
• A statement that the expert is familiar with the case and will give a meaningful deposition about their testimony, opinions and basis for those opinions
• A statement of the expert’s hourly and daily fees, both for depositions and for consulting with the attorney or party who retained the expert

Declarations are not required for certain types of experts, such as treating physicians. Even if a declaration is not required, however, the witness should still be designated by name and address.

If the party or their attorney does not intend to use any expert witnesses, they should state so in writing.

Failure to Meet Expert Witness Information Exchange Requirements

Generally speaking, if a party does not disclose an expert, including the expert’s declaration when required, produce writings included in the demand, or make their expert available for deposition, the court will not allow any evidence from that expert.

A few specific exceptions apply. For instance, a party may call a witness they did not designate, if the witness was designated by another party and has already been deposed. Likewise, a party may call an expert witness they did not designate in order to impeach the testimony of another party’s expert witness. In this second circumstance, however, the expert may not testify as to their own opinion, but may only provide testimony to show that a fact the other expert used to form their opinion is false or nonexistent.

A few specific exceptions apply. For instance, a party may call a witness they did not designate, if the witness was designated by another party and has already been deposed. Likewise, a party may call an expert witness they did not designate in order to impeach the testimony of another party’s expert witness. In this second circumstance, however, the expert may not testify as to their own opinion, but may only provide testimony to show that a fact the other expert used to form their opinion is false or nonexistent.