Expert Witnesses in Delaware
Under Delaware Rule of Evidence 702, an expert witness is a person who is qualified by knowledge, skill, experience, training, or education and who may testify in the form of an opinion or otherwise if their specialized knowledge will help the trier of fact understand the evidence or determine a fact in issue.
Rules Governing Disclosure
In Delaware, expert disclosures are often made through interrogatories or scheduling orders issued by the court. Unlike federal courts, a full written expert report is not always automatically required, unless ordered by the court.
Under Rule 26(b)(4)(A) of Delaware Superior Court Civil Rule, a party may require another party to identify each person expected to be called as an expert witness at trial.
The disclosure typically must include:
The identity of the expert
The subject matter on which the expert will testify
The substance of the facts and opinions to which the expert is expected to testify
A summary of the grounds for each opinion
Delaware Superior Court Civil Rule 37 allows the court to impose sanctions when a party fails to comply with discovery obligations, including expert disclosure requirements.
Admissibility Standards
Delaware admits expert testimony when the expert is qualified and the testimony is reliable, relevant, and helpful to the trier of fact, applying a Daubert-style reliability analysis under Rule 702.
Rule 702 makes the trial judge a “gatekeeper” responsible for ensuring that expert testimony is reliable before it reaches the jury.
Courts may consider factors such as:
Whether the theory can be tested
Whether it has been peer-reviewed
The known or potential error rate
The existence of standards controlling the technique
Whether the method is generally accepted in the relevant field
Attorney–Expert Communication Protection
Delaware recognizes work-product protection for certain communications between attorneys and expert witnesses. The rule provides that draft expert reports and many attorney–expert communications are protected from discovery.
However, the protection is not absolute.
Even though most communications are protected, the following must still be disclosed:
Compensation of the expert
Any communications regarding how much the expert is being paid.
Facts or data provided by the attorney
If the attorney supplied facts or data that the expert considered in forming opinions, those materials are discoverable.
Assumptions provided by counsel
Any assumptions supplied by the attorney that the expert relied upon when forming opinions must be disclosed.
Compensation
Delaware requires that the party who seeks discovery from an opposing expert pay that expert a reasonable fee, and the expert’s compensation arrangements are discoverable during litigation under Rule 26(b)(4).
Limits on Number of Expert Witnesses
The Delaware Superior Court Civil Rules do not set a default maximum number of experts a party may call. However, courts have authority to control expert testimony to prevent cumulative or unnecessary evidence.
Judges may issue pretrial scheduling orders that limit the number of expert witnesses or restrict the number of experts per subject area. This is often done to streamline complex litigation and reduce costs.
Out-of-State Expert Qualification
Delaware generally allows out-of-state experts to testify as long as they are qualified under Rule 702, though additional statutory requirements may apply in specific fields like medical malpractice.
For instance, Delaware imposes additional requirements under Title 18 § 6853. That statute requires:
an affidavit of merit from a qualified medical expert when filing the complaint.
The expert must:
be familiar with the applicable standard of care, and
usually practice in the same or similar field of medicine as the defendant.
However, the statute still allows out-of-state physicians to serve as experts if they meet those criteria.
State-Specific Statutes & Local Rules
Del. Super. Ct. Civ. R. 26(b)(4): Expert disclosures and discovery requirements
Del. R. Evid. 702: Admissibility standard of expert testimony
Del. Super. Ct. Civ. R. 37: Sanctions for non-compliance with discovery
