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Exclusion of Expert Report That Exceeds Scope of Evidence Code §730 Appointment

This article discusses three ways to attack the report of an Evidence Code §730 expert when the expert’s report goes beyond the scope of the expert’s §730 appointment.

California probate court judges frequently appoint “730 experts” in conservatorship and trust proceedings. A 730 expert is an expert appointed by the court under California Evidence Code §730, which provides:

When it appears to the court, at any time before or during the trial of an action, that expert evidence is or may be required by the court or by any party to the action, the court on its own motion or on motion of any party may appoint one or more experts to investigate, to render a report as may be ordered by the court, and to testify as an expert at the trial of the action relative to the fact or matter as to which the expert evidence is or may be required.


The court may fix the compensation for these services, if any, rendered by any person appointed under this section, in addition to any service as a witness, at the amount as seems reasonable to the court. Nothing in this section shall be construed to permit a person to perform any act for which a license is required unless the person holds the appropriate license to lawfully perform that act.


A 730 expert is essentially an expert appointed by the court to render a neutral opinion on a subject that is outside the expertise of the court. In probate court, the expert is often a neuropsychologist appointed to evaluate the mental capacity of a proposed conservatee in a conservatorship proceeding, or a person’s capacity to resist undue influence in a trust dispute.

It is not uncommon, however, for the expert to offer an opinion that exceeds the scope of the expert’s appointment. For example, an expert might be appointed to offer an opinion as to whether “Mr. Smith is susceptible to undue influence,” and opine not only that Mr. Smith is susceptible to undue influence, but also that Mr. Smith was in fact unduly influenced (by someone, usually another party to the litigation) months or years earlier.

It appears that there are currently three ways to attack the portion of the expert report that is beyond the scope of the 730 appointment: (1) argue that it is outside the scope of designation; (2) argue that the expert is not qualified to render the opinion; and (3) argue that the material relied upon in forming the opinion is speculative and unreliable. All three arguments would be made when the evidence is offered, but could also be set up through deposition questioning.

Testimony is Outside the Scope of Designation

We could not find a case addressing the admissibility of portions of a 730 expert’s report that exceeded the order of appointment. However, an order of appointment is most closely related to an expert designation. The argument can be made that a 730 expert acting beyond the scope of her appointment does not differ from a party’s expert opining beyond the scope of her designation. In general, if an expert exceeds her designation, the court may exclude any such testimony. See Piscitelli v. Friedenberg, 87 Cal. App. 4th 953, 967 n.2 (2001) (excluding an expert opinion, in part, because it was “beyond the scope of his expert designation”); Jones v. Moore, 80 Cal. App. 4th 557, 565 (2000) (“When an expert deponent testifies as to specific opinions and affirmatively states those are the only opinions he intends to offer at trial, it would be grossly unfair and prejudicial to permit the expert to offer additional opinions at trial.”); Bonds v. Roy, 20 Cal. 4th 140, 147 (1999) (“When an expert is permitted to testify at trial on a wholly undisclosed subject area, opposing parties similarly lack a fair opportunity to prepare for cross-examination or rebuttal.”).

For purposes of analysis, consider an order appointing a neuropsychologist “to perform an evaluation of the proposed conservatee with regard to mental functions pursuant to CA Probate § 810 et seq., including her susceptibility to undue influence and her need, if any for the protections of a conservatorship of the person and/or estate.” If the expert answered these questions in her report, but went on to opine that the proposed conservatee had capacity to change her estate planning documents, then she exceeded the scope of the order. Arguably, any discussion of this topic should be precluded.

Expert is Not Qualified to Offer Specific Opinion

An expert can only provide opinion testimony on topics within her expertise. The expert must possess “sufficient knowledge, skill, experience, training, or education to qualify as an expert on the subject matter of his/her testimony.” Cal. Evid. Code § 720; Sinaiko v. Sup. Ct., 122 Cal. App. 4th 1133, 1142 (2004). “‘The competency of an expert is relative to the topic and fields of knowledge about which the person is asked to make a statement. In considering whether a person qualifies as an expert, the field of expertise must be carefully distinguished and limited.'” People v. Williams, 48 Cal. 3d 1112, 1136 (1989) (citing People v. Kelly, 17 Cal. 3d 24, 39 (1976)). This is determined by “whether the witness has sufficient skill or experience in the field so that his testimony would be likely to assist the jury in the search for the truth, and no hard and fast rule can be laid down which would be applicable in every circumstance. Where a witness has disclosed sufficient knowledge, the question of the degree of knowledge goes more to the weight of the evidence than its admissibility.” Mann v. Cracchiolo, 38 Cal. 3d 18 (1985) (internal quotations and citations omitted); People v. Davis, 62 Cal. 2d 791, 801 (1965) (“Whether a psychologist qualifies as an expert on sanity in a particular case depends on the facts of that case, the questions propounded to the witness, and his peculiar qualifications.”). Under the facts discussed above, if it can be shown that the expert is not an expert in analysis of historical capacity, that portion of her opinion could be precluded.

The Material Relied Upon Is Speculative

Although experts may rely upon hearsay and similar inadmissible evidence, an expert may not rely on mere speculation or conjecture. Korsak v. Atlas Hotels, Inc., 2 Cal. App. 4th 1516, 1524 (1992) (“Whether a matter used by an expert consists largely of conjecture or speculation is another important consideration. The factors of necessity, reliability, and speculation or conjecture at least provide some guideposts for the judge in determining whether the proffered expert opinion satisfies the requirements of Evid. Code, § 801.”) (emphasis in original) (internal quotations and citations omitted); Jennings v. Palomar Pomerado Health Systems, Inc., 114 Cal. App. 4th 1108, 1117 (2003) (“[A]n expert’s opinion based on assumptions of fact without evidentiary support, or on speculative or conjectural factors has no evidentiary value and may be excluded from evidence.”) (internal quotations and citations omitted); see also Korsak, 2 Cal. App. 4th at 1526 (finding that an expert’s opinion was without value because the expert did not conduct a “scientific sampling,” but rather “made an unexplained, casual sampling of unknown sources” rendering “[t]he authenticity, reliability, or the representative nature of the responses . . . totally undeterminable.”). Thus, if it can be established that the evidence the evidence the expert relied upon in forming the portion of her report regarding the proposed conservatee’s historical capacity is speculative or otherwise unreliable, it could bar that portion of her opinion.

Loren Barr
by Loren Barr
Updated: October 28, 2020

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