Expert Witnesses in New Hampshire
In New Hampshire, expert witnesses are individuals with specialized knowledge, training, or experience who can assist the court in understanding complex issues. Their testimony is governed by the New Hampshire Rules of Evidence, particularly Rule 702, which outlines the criteria for admissibility.
Civil Cases: Disclosure Requirements
Governing Rules
Rule 27 of the Rules of the Superior Court of the State of New Hampshire governs expert witness disclosures in civil litigation.
New Hampshire Revised Statutes § 516:29-b (2024) governs the disclosure of expert testimony in civil cases.
Unless the parties agree otherwise or a court orders differently, if the expert is retained or specially employed, or their duties regularly involve giving expert testimony, that disclosure must include a written report signed by the expert. The report must contain:
All opinions the expert will express and the basis for them;
The facts or data considered in forming opinions;
Exhibits summarizing or supporting opinions;
Qualifications of the expert, including publications in the last 10 years;
Compensation paid for the study and testimony;
A list of other cases in which the expert has testified in the past 4 years.
Timing
A party shall make a disclosure of expert witnesses within 30 days of a request by the opposing party.
The disclosures must be made at times and in the sequence directed by the court. Absent specific directions or stipulation, expert disclosures must be made at least 90 days before trial. If the expert’s testimony is intended solely to rebut another party’s expert, the deadline is 30 days after the opposing party’s disclosure.
Criminal Cases: Disclosure Requirements
New Hampshire Rules of Criminal Procedure Rule 12 addresses expert witnesses — but only in the context of discovery obligations. Under Rule 12’s discovery provisions, parties must disclose certain information about expert witnesses before trial.
Defendant’s Disclosure Obligation:
At least 7 days before trial, the defendant must provide the State with:
• A list of the names of witnesses, including experts; and
• Any reports or written summaries related to those expert witnesses that the defendant intends to use in the case as well as a summary of each expert's qualifications.
If the case is likely to include expert testimony from either the prosecution or the defense, then both sides must come to the dispositional conference ready to discuss and agree on deadlines for all expert-related disclosures. This includes deadlines for:
Expert reports
– Any written reports, test results, examinations, scientific analyses, experiments, or statements that the expert prepared or relied on.
Expert qualifications
– A summary of each expert’s credentials, education, experience, and other information showing why they are qualified to testify.
Rebuttal expert disclosures
– Reports and qualifications of any experts who will testify solely to rebut or respond to the other side’s expert.
Expert depositions
– Scheduling when expert depositions will occur.
Except for good cause shown, the failure of either party to set expert witness disclosure deadlines at the dispositional conference may be grounds to exclude the expert from testifying at trial.
In a felony case, either side (prosecution or defense) is allowed to take a discovery deposition of any expert witness the other party plans to call at trial.
Communication Between Attorneys and Experts
New Hampshire law allows broad attorney-expert communication, often protected by work product doctrine and sometimes attorney-client privilege, but communications intended for disclosure (like expert reports) must be produced in discovery. The primary rules governing lawyer conduct (like Rule 4.2) focus on communication with represented parties, not typically retained experts who are part of the legal team.
Work Product Doctrine: Most interactions, including drafts of reports, attorney notes, and discussions about case strategy, are generally protected as attorney work product.
Attorney-Client Privilege: Privilege can extend to experts if they are acting as an agent of the attorney/client for the purpose of giving legal advice, but this is less common than work product protection.
Payment for Expert Discovery
For civil cases under the Superior Court Rules, there is no statutory or rule provision that imposes an automatic fee or payment obligation for expert discovery in the typical sense. Instead, parties are responsible for their own expert costs, including fees for reports or depositions, unless the court orders otherwise.
Limits on Number of Expert Witnesses
Unlike some jurisdictions that restrict the number of experts (for example, limiting multiple experts on the same subject matter), New Hampshire does not have a statute or rule that sets a numerical limit on how many expert witnesses a party may call in either civil or criminal cases.
Out-of-State Expert Qualification
Under New Hampshire Rule of Evidence 702 and RSA 516:29-a (the expert admissibility statute), the requirements for expert testimony are:
The expert must be qualified by knowledge, skill, experience, training, or education, and
Their testimony must be reliable and help the trier of fact.
Neither the rule nor the statute requires the expert to:
Live in New Hampshire,
Be licensed in New Hampshire, or
Practice professionally in New Hampshire.
Thus, experts from any state may testify if they meet the qualification and reliability requirements.
Rebuttal Experts
New Hampshire law allows parties to use rebuttal experts in both civil and criminal cases. There is no statutory limit on using rebuttal experts; however, courts regulate them through scheduling orders and discovery rules.
If a party fails to raise expert and rebuttal expert deadlines at the structuring conference without good cause, the court may exclude the expert at trial.
Sanctions for Failure to Disclose
1. Civil Cases — Sanctions Under Superior Court Rule 21 & Rule 35
In New Hampshire civil litigation, failure to disclose (including failure to disclose expert witnesses or expert reports) may result in a range of sanctions.
A. Superior Court Rule 27 (Expert Witnesses) — Expert-Specific Sanction
Rule 27 expressly states:
Failure to raise expert disclosure deadlines at the Structuring Conference, without good cause, may be grounds to exclude the expert from testifying.
This is a powerful, expert-specific sanction unique to New Hampshire practice.
B. RSA 516:29-b (Expert Disclosures in Civil Cases)
Under this statute:
Expert disclosures must be made at least 90 days before trial (or 30 days for rebuttal experts), unless the court orders otherwise.
Courts may exclude expert testimony for late disclosure.
Although the statute does not list detailed sanctions, NH courts routinely apply exclusion under this section.
2. Criminal Cases — Sanctions Under New Hampshire Criminal Rule 12
Under Rule 12 (Discovery), failure to disclose required information (including expert witnesses, expert reports, scientific test results, or rebuttal experts) may lead the court to:
Order disclosure,
Grant a continuance,
Prohibit the party from introducing the evidence or witness, or
Enter any order that justice requires.
Exclusion of the witness is a recognized remedy, though courts use it carefully in criminal cases to avoid violating constitutional rights.
