Connecticut Expert Witness Disclosure Rules

Expert Witnesses in Connecticut

An expert witness in Connecticut is an individual possessing specialized knowledge, skill, experience, training, or education, who provides opinions in court to assist the trier of fact in understanding evidence or determining facts in issue.

Rules Governing Disclosure

The primary rules for expert witness disclosures in Connecticut are governed by the Connecticut Practice Book, specifically § 13-4 for civil cases and § 40-13 for criminal cases.

In civil matters, Practice Book § 13-4(b) mandates the disclosure of expert witnesses a party intends to call at trial. This disclosure must be made within a reasonable time before trial and is subject to modification by court order.

Content of Disclosure

Under Practice Book § 13-4(b), the disclosure must include:

· Expert's Name, Address, and Employer: Identifying information for the expert witness.

· Subject Matter: The area or subject matter on which the expert is expected to testify.

· Expert Opinions: The expert opinions to which the witness is expected to testify

· Substance of Facts and Opinions: A summary of the facts and opinions to which the expert is expected to testify.

· Summary of Grounds: A summary of the grounds for each opinion.

· Written Report: The written report for the expert witness; if any.

The required information may be provided by referring, in the disclosure, to the expert witness’s written report that contains this information.

Timing of Disclosure

Except for a treating health care provider, and unless otherwise ordered by the court or agreed to by the parties, a party who discloses an expert witness must, upon request by an opposing party, produce to all other parties any materials obtained, created, or relied upon by the expert in forming his or her opinions in the case, no later than fourteen days before the expert’s deposition.

Written Report Requirement – Expert Witnesses in Connecticut

Connecticut’s rules do not explicitly require a written report from expert witnesses in civil litigation under Practice Book § 13-4(b). However, the substance of the expert's expected testimony must still be disclosed, and if a written report exists, it must be provided as part of the disclosure. Here's a detailed breakdown:

When a Written Report Is Not Required (No Report Prepared)

If the expert has not prepared a report, the party disclosing the expert must still provide the following in their disclosure:

Expert's Identifying Information:

· Name

· Address

· Employer

Subject Matter:

· The specific area or topic the expert will address at trial.

· Substance of the Testimony:

· A summary of the facts and opinions the expert is expected to offer.

Basis for Opinions: A summary of the grounds or reasoning for each opinion the expert will express.

Note: Failure to disclose this information in sufficient detail may result in the exclusion of the expert’s testimony.

When a Written Report Is Prepared

If the expert has prepared a written report, the disclosure must include:

· All information required in cases without a report, plus:

· The Written Report Itself:

· The full report must be provided to opposing counsel.

· The report should contain: All opinions the expert intends to express.

· The facts and data considered in forming those opinions.

· Any exhibits the expert intends to use to support the opinions.

· Any publications or literature relied on in reaching conclusions.

Unlike federal rules, Connecticut’s rules do not automatically require the production of a detailed, signed report. However, if the expert has created one, it must be shared.

Timing of Submission

Connecticut law does not define a specific interval between expert disclosure and the submission of a written report. However:

· It must be provided within a reasonable time before trial.

· Courts may impose case-specific deadlines through scheduling orders.

· Courts may exclude testimony if the report (or summary) is not timely disclosed.

Admissibility Standards

Connecticut employs a Daubert-like standard for expert admissibility, as defined in State v. Porter, 241 Conn. 57 (1997). The Connecticut Code of Evidence Section 7-2 requires that expert testimony:

· Assists the trier of fact.

· Is based on enough facts or data

· The underlying reasoning or methodology is scientifically valid.

· The reasoning or methodology underlying the scientific theory or technique can be applied to the facts in issue.

Trial judges act as gatekeepers for expert testimony, especially when it is scientific or technical in nature. Even non-scientific experts who base their opinions on experience must demonstrate that their testimony is both relevant and reliable.

Attorney-Expert Communication Protection

In Connecticut, the protection for communications between an attorney and an expert witness largely depends on whether the expert is expected to testify at trial or is retained only as a consulting expert. Communications with testifying experts may be discoverable, while those with consulting experts are generally protected as attorney work product.

Key Distinctions in Connecticut Law

Testifying Experts

Connecticut courts require the disclosure of a testifying expert's identity, the subject matter of their testimony, and the substance of all facts and opinions they will present, including the grounds for those opinions.

· Discoverability: Under Connecticut Practice Book § 13-4(b)(3), a party must produce all materials obtained, created, or relied upon by the expert in forming their opinions. Lower courts have often interpreted this broadly, suggesting that even materials that would otherwise be considered attorney work product, if shared with a testifying expert, become discoverable to allow the opposing side to probe for attorney influence.

· No Automatic Privilege for Communications: Unlike in federal court (under the amended Fed. R. Civ. P. 26), which provides explicit work-product protection for most attorney-expert communications and draft reports, Connecticut has no parallel rule. This lack of a clear rule has led to varied trial court rulings, with the weight of authority favoring the discoverability of materials provided by an attorney to a testifying expert.

Consulting Experts

Information regarding experts retained solely for consultation, who are not expected to be called as a witness at trial, is generally not discoverable.

· Protection: Their identity and opinions are protected unless the party seeking discovery can show "exceptional circumstances under which it is impracticable... to obtain facts or opinions on the same subject by other means".

Payment for Expert Discovery

· Under Conn. Gen. Stat. § 52-260, there are statutory provisions for “witness fees.” The statute provides nominal per diem and mileage (for state-summoned witnesses).

· Importantly, when the witness is a “practitioner of the healing arts” (e.g. physician), a psychologist, a real estate appraiser, etc., and gives expert testimony (even by deposition), the court “shall determine a reasonable fee ... and tax it as part of the costs, in lieu of all other witness fees.”

· Under CPB § 13-4(c), as applied to expert witnesses, when an expert disclosed under § 13-4(b) is deposed, the party seeking the deposition generally must pay a reasonable fee for the expert’s time for the deposition (excluding preparation time unless otherwise agreed); and reimburse reasonable travel or related expenses.

· If parties have agreed otherwise (or the court orders otherwise), the allocation or adjustment of compensation may be modified.

Limits on the Number of Expert Witnesses

Connecticut does not impose a specific limit on the number of expert witnesses a party may call. However, the court has the discretion to limit expert testimony to prevent cumulative or redundant evidence and to ensure a fair and efficient trial.

Out-of-State Expert Qualification

Out-of-state experts are not restricted from testifying in Connecticut courts, but their qualifications must be sufficient to meet the standard under Connecticut Evidence Code § 7-2.

Medical Malpractice Exception:

General Statutes § 52-184c defines who is qualified to testify as an expert on the standard of care in a medical malpractice action.

(a) When the expert practices in the same specialty

To testify against a defendant, the expert must:

Be trained and experienced in the same specialty as the defendant; AND
Be board-certified in that specialty if the defendant is board-certified.

(b) When the expert practices in a different but similar specialty

If no expert from the identical specialty is used, a witness from a related specialty may testify if:

They are trained and experienced in a medical specialty with a “similar standard of care” for the treatment or procedure at issue; AND
They can show that their clinical practice or instruction involves the same or similar procedures.

This prevents exclusion of experts in overlapping specialties (e.g., emergency medicine vs. internal medicine).

The expert must:

Be actively practicing, or
Have recently practiced (in the same or similar specialty).

Active practice includes:

Clinical care
Teaching at an accredited medical school
Supervisory roles in clinical settings

This prevents testimony from purely academic or long-retired experts with no current practice experience.

(d) Limits on testimony

The expert’s testimony is limited only to the issues for which they are qualified under subsections (b) or (c).
They cannot opine on areas outside their training or recent practice.

For example:
A cardiologist may testify about cardiac procedures but not neurosurgical protocols.

While most civil cases do not require formal declarations at the time of expert disclosure, Conn. Gen. Stat. § 52-190a imposes a pre-filing certification requirement under which a Plaintiff must attach a written and signed opinion letter from a “similar health care provider” in addition to a Good-Faith Certificate.

Rebuttal Experts

Connecticut law permits rebuttal experts, but only when their testimony directly responds to new matters raised by the opposing party’s expert; courts strictly forbid using rebuttal experts to introduce new affirmative opinions and exercise broad discretion in allowing or excluding such testimony.

Precedents

· Wexler v. DeMaio, 279 Conn. 168 (2005): The court held that a party's failure to comply with expert disclosure requirements justified precluding the expert's testimony.

· Gianetti v. Neigher, 2022 WL 1672910 (Conn. App. Ct. 2022): The court affirmed the trial court's decision to preclude expert testimony due to the plaintiff's failure to comply with disclosure deadlines and requirements.

Failure to Make Discovery

Under Practice Book § 13-4(h), the court may impose sanctions on a party that fails to comply with the requirements of this section after conducting a hearing. However, an order precluding an expert witness’s testimony may be issued only if the court determines that: (1) the sanction of preclusion—considering its impact on the party’s ability to prosecute or defend the case—is proportionate to the noncompliance, and (2) the noncompliance cannot be effectively remedied by a less severe sanction or a combination of lesser sanctions.

Expert Disclosure Rules in Criminal Procedure (Practice Book § 40-13)

Practice Book § 40-13 is designed to ensure that both sides in a criminal case—the State and the defendant—receive timely notice when the opposing party intends to call an expert witness.
This rule prevents “trial by ambush” and allows adequate time to prepare for cross-examination, investigation, or rebuttal.

1. When Disclosure Is Required

Expert disclosure is not automatic.
It is triggered only when a party makes a written request to the opposing side.

Once such a request is made, the party intending to use an expert must provide full disclosure.

2. What Must Be Disclosed

Under § 40-13, the disclosing party must provide:

(a) The expert’s name and business address

This identifies who will testify.

(b) The subject matter of the expected testimony

What field or area the expert will address (e.g., DNA, ballistics, toxicology, psychiatry).

A summary of the conclusions the expert will offer at trial.

(d) The substance of the grounds for those opinions

The foundational basis—tests, methods, principles, examinations, or data relied upon.

(e) Results or reports of examinations or tests

This includes:

Lab reports
Forensic test results
Scientific evaluations
Medical findings

These must be produced or made available for inspection.

4. Timing

Disclosure must be made within a reasonable time before trial, or as directed by a court order.

The Connecticut Rules Governing Expert Witness Disclosure and Testimony