An Evidence Code 730 evaluation is an investigation performed by a neutral expert the judge appoints under California Evidence Code section 730 when a case turns on a question that requires specialized knowledge. The expert works for the court rather than for either side, examines the specific issues the judge identifies, and submits a written report that both parties receive. You keep the right to cross-examine that expert at trial and to hire your own expert to offer a competing opinion.
When and How the Court Orders One
A judge can appoint a 730 expert at any point before or during trial, either on the court’s own initiative or in response to a motion from either party.1California Legislative Information. California Evidence Code 730 – Appointment of Expert Witness by Court The threshold is low: if it appears expert evidence is or may be needed, the court has authority to bring someone in. Nothing requires the parties to first try to resolve the technical question on their own.
Once the judge decides to appoint, the court issues a formal order defining what the expert will investigate. That order sets the boundaries. The expert can only examine the issues the court specifies, and neither party can expand or narrow the scope without going back to the judge. The limitation keeps the investigation focused and prevents drift into areas the court didn’t authorize.
Parties often get input on who is appointed. Judges may invite nominations and will frequently appoint someone the parties agree on, though the final choice rests with the court. The appointee must hold the appropriate professional license for any act that requires one, so a psychologist evaluating a parent must hold a valid California psychology license.1California Legislative Information. California Evidence Code 730 – Appointment of Expert Witness by Court Qualification otherwise follows Evidence Code 720, which looks for special knowledge, skill, experience, training, or education on the subject at issue.2California Legislative Information. California Evidence Code 720
What the Expert Will Actually Do
What the investigation looks like depends on the kind of case. In a custody dispute, the expert typically interviews both parents and the children, observes parent-child interactions, reviews school and medical records, and may administer psychological testing. In a construction defect case, the expert might inspect the property and analyze engineering reports. In other matters it could involve reviewing documents, examining physical evidence, or conducting specialized testing.
The expert then compiles the findings into a written report submitted directly to the court. The report lays out the conclusions and explains the methods used to reach them. Copies go to every attorney of record, so no party is blindsided by its contents.3Superior Court of California, County of Orange. Order Appointing Expert (EC 730) That report often anchors the court’s analysis of the technical issue.
After the report is filed, the expert may testify at trial or at an evidentiary hearing. Evidence Code 732 gives every party the right to call and examine the court-appointed expert, and when the court itself calls the expert, every party has the right to cross-examine.4Justia Law. California Evidence Code 730-733
Custody Evaluations Under Rule 5.220
Family law is where most people encounter a 730 evaluation. In contested custody or visitation disputes, the court can appoint a child custody evaluator under Family Code 3110 or directly under Evidence Code 730. California Rules of Court, rule 5.220, governs both court-connected and private evaluators appointed through either route.5Judicial Branch of California. Rule 5.220 Court-Ordered Child Custody Evaluations
Custody evaluators face additional qualification requirements beyond the general expert standard. Under Family Code 3110.5, all custody evaluators must complete a domestic violence and child abuse training program and comply with education, experience, and training requirements set by the Judicial Council.6California Legislative Information. California Family Code 3110.5 Evaluators must use comparable assessment procedures for all parties and must inform each adult about the purpose, nature, and method of the evaluation before it begins.
The resulting report includes recommendations about custody and visitation arrangements. Judges rely heavily on these reports, but they are not required to follow the recommendations.
Who Pays
The court sets the expert’s compensation at an amount it considers reasonable, as authorized by Evidence Code 730 itself.1California Legislative Information. California Evidence Code 730 – Appointment of Expert Witness by Court How that cost gets divided depends on the type of case.
In civil cases, including family law matters, Evidence Code 731 directs the court to apportion the expert’s fees among the parties in whatever proportion the judge decides. Those costs can then be taxed like other litigation costs at the end of the case. Judges typically consider each party’s financial resources and which party’s issues prompted the need for the expert. In criminal cases and juvenile court proceedings, the county pays the expert out of the county treasury.7California Legislative Information. California Evidence Code 731
Expect to pay your share of the retainer and ongoing fees as a condition of the litigation. Failure to comply with the court’s payment order can lead to sanctions or limit your access to the expert’s findings.
What the Report Means for Your Case
The expert’s neutral status carries real weight with judges. Because the expert wasn’t hired by either side, the conclusions tend to be treated as a credible baseline. Influential is not the same as unassailable, though. The report’s testimony gets weighed like any other evidence, and judges are not required to adopt the expert’s conclusions.
You also keep the right to hire your own expert. Evidence Code 733 preserves every party’s right to present independent expert testimony on the same issue the court-appointed expert addressed.8California Legislative Information. California Evidence Code 733 The catch is financial: you pay the full cost, and only ordinary witness fees can be recovered as costs in the case. Treating an unfavorable 730 report as the final word is a mistake. It’s a starting point for the court, not the end of the conversation.
Challenging the Findings
Disagreeing with the expert’s conclusions isn’t enough on its own. To persuade the judge to disregard or deviate from the report, you need to attack its foundation. The most effective challenges focus on methodological problems: did the expert use outdated techniques, ignore relevant data, apply an inappropriate standard, or reach conclusions that don’t follow from the evidence they gathered?
Your options for pushing back include:
- Cross-examination at trial under Evidence Code 732, which is your best opportunity to expose weaknesses in the analysis in front of the judge.
- Hiring a rebuttal expert under Evidence Code 733 to submit a competing report and testify with an alternative opinion.8California Legislative Information. California Evidence Code 733
- Filing objections to specific portions of the report before trial, particularly if the expert exceeded the scope of the court’s order or relied on inadmissible information.
- Requesting a supplemental evaluation if new facts emerge after the report is completed.
Bias and conflict of interest are also valid grounds for challenge. A prior relationship with the opposing party, a financial interest in the outcome, or demonstrated partiality during the investigation can undermine the report’s credibility or lead to the expert’s removal. The burden falls on the challenging party to present concrete evidence of the problem rather than vague allegations of unfairness.