1. Civil Pretrial Practice
Expert Discovery

2. Expert Discovery Retained versus Non-Retained Experts
Expert witnesses will generally have specialized knowledge of a scientific or technical field. There are two categories of expert witnesses:
Retained experts are witnesses with expertise, specifically retained by you to express an opinion in anticipation of the litigation or in preparation for trial.
Non-retained experts, are percipient witnesses who can be called upon to give their expert opinions based on their observations, gained not in anticipation of litigation or preparation of trial.
Although a treating physician is a percipient expert, that does not mean that his or her testimony is limited only to personal observations. A treating physician can provide opinion testimony based on the facts independently acquired and informed by the physician’s training, skill, and experience.

3. Expert Discovery - Dates and Deadlines
Experts Must Be Demanded – 70 days before trial (or within 10 days of setting trial date, whichever is closer to trial date)  [CCP ]
Experts Must Be Disclosed – 50 days before trial (or 20 days after service of demand, whichever is closer to trial date)  [CCP ]
Supplemental Expert Disclosure – Must be disclosed within 20 days of the Exchange of Expert Witnesses.  May only disclose witness to cover a subject covered by opponent’s witnesses.  [CCP ]
Expert Discovery Cut Off – 15 days before original trial date.  [CCP ].
Last Day for Motions Regarding Experts – 10 days before original trial date.  [CCP ].

4. Expert Discovery Demand for Exchange of Expert Witness Information
The demand for exchange of expert witness information must include (CCP § ):
The name of the party making the demand (i.e., your client) below the title of the case;
A statement that the demand is being made under CCP §§ ;
The specific date you have calculated for exchange of:
Lists of expert trial witnesses,
Expert witness declarations, and
Any demanded production of writings; and
If you want to see an expert’s reports and writings, a demand for inspection and copying of all discoverable reports and writings made by the expert witness in the course of preparing his or her opinion. CCP § (c).
If a party has demanded production and exchange of expert witness information, all parties, including the party initiating the demand, must produce and exchange them at the place and on the date specified in the demand.

5. Expert Discovery Designation of Expert Witnesses
This is a formal, written statement, including either:
A statement that you do not intend to offer any expert witness testimony (CCP § (b)(2)); or
A list of the names and addresses of anyone whose expert opinion you expect to offer in evidence. CCP §§ (a),  (b)(1).
This can include: a party, an employee of a party, or someone you have hired to express an opinion in anticipation of litigation or in preparation for trial. CCP § (b). It also includes any percipient witness you expect to ask for his or her expert opinion (e.g., a police officer who investigated a traffic accident or the architect who designed a building that is the subject of the litigation). CCP § (a)(3).
If you intend to use a treating physician as an expert, include him or her on your list.
See Schreiber v Estate of Kiser (1999) 22 C4th 31, 91 CR2d 293 (expert witness declaration generally not required for treating physician; but if treating physician is formally retained for purpose of offering opinion testimony at trial, party must provide expert designation, with physician’s name and address, although expert declaration not required); Kalaba v Gray (2002) 95 CA4th 1416, 116 CR2d 570 (trial court correctly rejected standard of care testimony from plaintiff’s treating physicians who were not designated as expert witnesses; absence of expert testimony on standard of care resulted in nonsuit for defendant).

6. Expert Discovery Expert Witness Declarations
You will need an expert witness declaration if any expert witness on your list is in a category identified in CCP § (b).
You do not need an expert declaration for an expert witness who is not in one of the categories of CCP § (b) (i.e. non-retained experts). CCP §
This is a statement, signed by you as the party’s attorney, setting out specific information and executed under penalty of perjury, which must contain:
A brief statement of the expert’s qualifications (CCP § (c)(1));
A brief statement of the general substance of the testimony that the expert is expected to give at trial (CCP § (c)(2));
The trial court can preclude an expert from testifying at trial on a subject if its general substance was not described in the expert witness declaration and the opposing party has had no notice of it.
A representation that the expert has agreed to testify at the trial (CCP § (c)(3));
A representation that the expert will be familiar with the case and will give a meaningful oral deposition about his or her testimony, opinions, and their basis (CCP § (c)(4)); and
A statement of the expert’s hourly and daily fee for providing deposition testimony and for consulting with the retaining attorney (CCP § (c)(5)).

7. Expert Discovery Supplemental Designation of Expert Witnesses
You may serve a supplemental designation list within 20 days of the original exchange, providing you meet the following qualifications:
You engaged in the original exchange; and
You did not retain an expert to testify on a subject; i.e., you did not originally intend to cover that subject wit expert testimony; but you want to add an additional expert to testify on that subject because you have learned that opposing counsel is naming an expert witness to cover that subject.
To add an expert to testify on the same subject as experts designated in the original exchange by opposing party, you must provide (CCP § (a)-(b)):
Supplemental list of names and addresses of expert witnesses you are retaining to testify;
Expert witness declarations; and
Discoverable reports and writings, if any, made by the additional experts.

8. Expert Discovery Failure to Designate Expert Witnesses
If a party does not disclose their experts, include an expert declaration when required, produce reports and writings of experts demanded under CCP § , or make their expert available for deposition, the court must exclude any evidence from that expert (CCP § ), except under a few narrow circumstances (CCP § ).
The court will exclude your expert’s opinion if you unreasonably fail to timely (CCP § ):
List your expert witness,
Submit your expert witness’s declaration,
Produce discoverable reports and writings, if demanded, or
Make your expert witness available for deposition

9. Expert Discovery - Depositions
Timing: Expert Depositions may be set “On receipt of an expert witness list from a party.”  [CCP ]
Location and Cost : If one side discloses an expert who is "specially retained" or a party or an employee of a party, the designating party must produce that expert for deposition within 75 miles of the courthouse. (Code Civ. Proc. § 2034(i)(1).) The noticing party must pay the expert a reasonable hourly rate for actual deposition time.
Document Request With Deposition Notice: California Code of Civil Procedure § requires that the parties exchange "all discoverable reports and writings" that are "made in the course of preparing that expert’s opinions" when a party includes that request in the demand for exchange of expert information. (Code Civ. Proc. §§ 2034(a)(2) and (g).)
Experts must provide a copy of the documents that they are producing in response to the deposition notice three business days before their deposition.  [CCP ]