## Facts

- Plaintiffs Brenda Minner, Hillard Muttart, Linda Brennan, and James Brennan sued over illnesses they attributed to conditions in the Discover Card/Greenwood Trust Company office building at 12 Reads Way, New Castle, Delaware.
- Greenwood Trust leased the building from defendant American Mortgage & Guaranty Company (AMGC), and defendant Emory Hill Management Company managed the building for AMGC.
- Plaintiffs alleged that environmental conditions in the building caused them “building-related” physical and psychological problems; the court described the matter as a “sick building” case involving complicated medical and psychological complaints.
- Because causation and damages turned on specialized testimony, both sides designated multiple witnesses in medical and related fields and challenged the opposing side’s proposed testimony.
- The case came to the Superior Court of Delaware (New Castle County) before trial on an omnibus set of motions in limine addressing admissibility of proposed witness opinions under Delaware Rule of Evidence 702 and federal reliability cases such as *Daubert*, *Joiner*, and *Kumho Tire*.

## Issues

1. Under Delaware Rule of Evidence 702 and the reliability approach reflected in *Daubert*, *Joiner*, and *Kumho Tire*, which proposed witness opinions in this sick-building case were sufficiently reliable and helpful to be presented to the jury?
2. When, if ever, may medical causation opinions based mainly on sequence in time (symptoms after exposure) satisfy Rule 702’s reliability requirement?
3. If a witness has reliable bases for some subjects but not others, should the court exclude the witness entirely or restrict the testimony to the reliable areas?

## Decision

- The court issued an opinion and order resolving twelve motions in limine aimed largely at excluding or restricting proposed testimony; it did not decide liability or damages.
- Plaintiffs’ two motions to exclude defense witnesses were denied.
- Of defendants’ motions challenging plaintiffs’ witnesses, one motion was granted, seven were granted in part and denied in part, and two were denied.
- Defendants’ separate motion to strike an affidavit was deemed moot.
- Applying Rule 702’s screening function, the court admitted opinions supported by reliable methods and a sufficient connection to the facts, while excluding or limiting opinions that rested on speculation, weak foundations, or an unreliable causal link—particularly where the reasoning relied chiefly on timing rather than a tested or otherwise reliable medical/scientific basis.

## Legal Principles

- Delaware Rule of Evidence 702 requires that opinion testimony be given by a qualified witness and be based on sufficient facts or data, reliable principles and methods, and a reliable application of those methods to the case.
- The trial judge must screen proposed testimony for reliability and relevance, focusing on the soundness of the method used and whether the opinion will help the jury decide a disputed fact.
- *Daubert* factors (such as testing, peer review, error rate/controls where suitable, and general acceptance) may guide the reliability inquiry, but the analysis is flexible and depends on the subject matter and the type of opinion offered.
- *Joiner* permits the court to examine the link between the data and the conclusion; a large analytical gap can justify exclusion even if some underlying materials appear sound.
- *Kumho Tire* extends reliability screening beyond purely scientific testimony to technical and other specialized subjects when offered under Rule 702.
- A causation opinion based only on a temporal sequence—symptoms occurring after an exposure—does not, by itself, show a reliable causal method; more is required to connect exposure and injury in a way Rule 702 accepts.
- When a witness is reliable on some matters but not others, limiting the scope of testimony is an available remedy; weaknesses that do not rise to unreliability may be left for cross-examination and competing proof.

## Conclusion

*Minner v. American Mortgage & Guaranty Co.* is a pretrial evidentiary decision in a sick-building personal-injury suit in which the Delaware Superior Court applied D.R.E. 702 and the *Daubert* line of cases to multiple motions in limine, denying plaintiffs’ exclusion motions, granting one defense motion, partially granting seven others, and denying two, while stressing that causation testimony must rest on reliable methods and not merely on the fact that symptoms followed alleged exposure.


Minner v. American Mortgage & Guaranty Co., 791 A.2d 826 (2000)