Delaware Expert Witness Rules: What Litigators Need to Know

Delaware's approach to expert witnesses is firmly rooted in its civil procedure rules and shaped by a combination of state court precedent and localized judicial discretion. Known for its prominence in corporate and complex litigation, Delaware demands a high degree of diligence in expert disclosures, qualifications, and evidentiary foundations. Attorneys must comply with procedural rules while carefully anticipating both admissibility challenges and strategic discovery limitations.

Designation Requirements

In Delaware, expert witness designation is governed by Superior Court Civil Rule 26(b)(4) and case-specific scheduling orders. There is no formal “designation” motion process; instead, experts are identified through mandatory disclosures or responses to interrogatories.

The party must disclose:

• The identity of each expert
• The subject matter of expected testimony
• A summary of opinions
• The basis and reasons for those opinions

Failing to identify an expert within court-ordered deadlines or failing to sufficiently summarize their opinions may result in preclusion under Rule 37. Delaware courts take compliance seriously and will enforce sanctions where surprise or prejudice results from inadequate or late disclosures.

Expert Disclosure Process

Expert exchange in Delaware is heavily influenced by court-issued scheduling orders, particularly in Superior Court and Court of Chancery litigation. Under Del. Super. Ct. Civ. R. 26(b)(4), the rules allow discovery of the following regarding testifying experts:

• Qualifications and prior testimony
• Written reports, if provided
• Summaries of expected testimony
• Materials considered in forming opinions

Parties are typically required to produce expert disclosures by a date set in the scheduling order, which often differentiates between opening, rebuttal, and sur-rebuttal experts. Although not mandatory, written reports are commonly exchanged, especially in technical or scientific matters.

In medical malpractice cases, experts must meet statutory qualifications under 18 Del. C. § 6854, and disclosures must align with requirements for filing a Certificate of Merit.

Required Declarations

Delaware does not require expert affidavits or declarations as part of initial disclosure. However, such documentation becomes critical at the summary judgment stage. Under Del. Super. Ct. Civ. R. 56(e), affidavits supporting or opposing motions must:

• Be made on personal knowledge
• Contain facts admissible in evidence
• Show affirmatively that the witness is competent to testify

In medical negligence actions, Delaware requires a Certificate of Merit to be filed with the complaint or shortly thereafter. This must be signed by an expert licensed in the same field as the defendant and must state that the defendant breached the applicable standard of care.

Fees and Compensation

Expert witness fees in Delaware are not capped by statute but are subject to scrutiny for reasonableness. When an opposing party seeks to depose a testifying expert, that party must pay the expert a reasonable fee for time spent in deposition, consistent with Rule 26(b)(4)(C).

Courts may resolve disputes over excessive or obstructive billing practices, particularly where the requested rate significantly exceeds the expert’s typical charges. Compensation for preparation time may also be allowed, depending on the complexity of the subject matter and the scope of deposition.

Discovery Scope and Limitations

Delaware permits targeted expert discovery under Rule 26(b)(4). Parties are entitled to discover:

• The identity and qualifications of experts
• A summary of opinions
• The basis and methodology used
• Documents and data relied upon

However, Delaware courts limit discovery of consulting experts—those retained in anticipation of litigation but not expected to testify—unless the opposing party can show exceptional circumstances warranting disclosure.

Additionally, Delaware courts often protect draft reports and attorney-expert communications under the work-product doctrine, especially where those materials contain legal strategy or impressions. Still, facts or data considered in forming expert opinions are discoverable.

Admissibility Standards

Delaware follows a Daubert-like standard for expert admissibility, codified in Delaware Rule of Evidence 702. In M.G. Bancorporation v. Le Beau, 737 A.2d 513 (Del. 1999), the Delaware Supreme Court adopted a gatekeeping role for trial judges in assessing expert reliability.

Under D.R.E. 702, expert testimony must meet the following criteria:

• The expert is qualified by knowledge, skill, experience, training, or education
• The testimony will assist the trier of fact
• The opinion is based on sufficient facts or data
• The opinion is the product of reliable principles and methods
• The expert has applied the methods reliably to the facts of the case

Trial judges may conduct Daubert hearings to evaluate the reliability and relevance of the expert’s methodology. In complex or high-value commercial cases, especially in the Court of Chancery, experts are often challenged pretrial via motions in limine or through pretrial stipulations narrowing the scope of testimony.

Key Deadlines & Strategy Notes

Expert deadlines are dictated by each court’s scheduling order. In Superior Court and Chancery Court, standard litigation tracks often include:

• Opening expert reports: 90–120 days before trial
• Rebuttal expert reports: 30–60 days after opening disclosures
• Discovery cutoff: Set well in advance of trial, often 30–45 days before
• Motions to exclude experts: Due per pretrial motion schedule

Delaware courts demand adherence to these deadlines, and late-disclosed opinions—even from properly identified experts—may be excluded. Attorneys are advised to meet all disclosure requirements precisely, and to ensure their experts are prepared for rigorous admissibility scrutiny.

State-Specific Statutes & Local Rules

• Del. Super. Ct. Civ. R. 26(b)(4): Governs expert disclosures and discovery
• Del. R. Evid. 702: Standard for admissibility of expert testimony
• Del. Super. Ct. Civ. R. 37: Permits sanctions for noncompliance with discovery
• Del. Super. Ct. Civ. R. 56(e): Affidavit requirements at summary judgment
• 18 Del. C. § 6854: Qualifications for expert witnesses in medical malpractice
• M.G. Bancorporation v. Le Beau, 737 A.2d 513 (Del. 1999): Leading case on expert admissibility

Each Delaware court, including Superior Court, Chancery Court, and Family Court, may impose case-specific orders governing the timing and scope of expert disclosures. Attorneys should consult with assigned judges or case management orders for court-specific practices.