## Facts

- Benjamin Harrison, age 70, injured two fingers while using a Craftsman 6 1/8-inch jointer-planer purchased from Sears and designed/manufactured by Emerson.
- Plaintiffs alleged a design defect: an unguarded aperture near the on–off switch that allowed Harrison’s left hand to contact the rotating blade.
- Plaintiffs sued Sears for negligence and breach of warranty and later added Emerson for its role in design, testing, manufacture, and sale.
- The parties disputed whether the accident could have occurred as Harrison described; defendants used an x-ray and engineering expert testimony to challenge the injury mechanics.
- Plaintiffs sought to support their theory with expert causation testimony and evidence of post-accident design changes removing the aperture.
- Harrison died of unrelated causes during the litigation; his estate was substituted as plaintiff.

## Issues

1. Whether the district court abused its discretion by admitting an x-ray and permitting a non-physician engineering expert to use it in accident reconstruction, and whether the related jury instruction was misleading.
2. Whether exclusion of portions of plaintiffs’ medical expert’s causation testimony warranted a new trial.
3. Whether the district court abused its discretion by admitting “negative evidence” that there were no prior similar complaints or accidents involving the product model.
4. Whether exclusion of evidence and cross-examination concerning post-accident design changes was erroneous under Federal Rules of Evidence 407 and 403, including when offered for impeachment.

## Decision

- The jury returned a verdict for defendants; on a special interrogatory, it found Harrison was not injured by unintentionally inserting his fingers into the aperture.
- The district court entered judgment for defendants and denied plaintiffs’ motion for a new trial.
- The First Circuit affirmed, holding the challenged evidentiary rulings were within the trial court’s discretion and any error did not warrant reversal.

## Legal Principles

- Evidentiary rulings, including expert qualification, demonstrative/physical evidence, and limiting instructions, are reviewed for abuse of discretion; reversal requires prejudicial error affecting substantial rights.
- A non-physician expert may rely on and discuss medical imaging for reconstruction purposes when the testimony is within the expert’s technical competence and is properly limited to that purpose.
- Exclusion of evidence may be harmless when the substance is cumulative and unlikely to affect the verdict in light of the full trial record and the jury’s findings.
- Evidence of absence of prior similar incidents may be admissible if supported by an adequate foundation and treated as probative but not conclusive on product safety or causation.
- Subsequent remedial measures are generally inadmissible to prove negligence or defect; even when offered for impeachment, the court may exclude the evidence under Rule 403 where probative value is substantially outweighed by unfair prejudice or misuse by the jury.

## Conclusion

The First Circuit upheld a defense verdict in a product-injury trial, concluding that the district court acted within its discretion in managing expert and evidentiary disputes, including allowing limited use of an x-ray for reconstruction, admitting properly grounded absence-of-complaints evidence, and excluding post-accident design-change evidence where its impeachment value was outweighed by the risk of an improper inference of negligence.


Harrison v. Sears, Roebuck & Co., 981 F.2d 25 (1st Cir. 1992)