What You'll Learn

  • The shared starting point 4. How to choose the claim
  • Trespass to chattels 5. Digital and copied information
  • Conversion

Educational information only; not legal advice. This article is a general study aid and should be checked against current authority and course materials.

1. Start with Intentional Interference

The defendant must intentionally engage in the act affecting the chattel. The defendant need not necessarily intend to violate the plaintiff's legal rights. Good-faith mistake can affect the seriousness analysis but does not automatically eliminate liability.

Claim Required interference Typical remedy

Trespass to chattels Impairment, substantial deprivation of use, bodily harm, or harm to another protected interest. Actual damages tied to the interference.

Conversion Dominion or control so serious that full-value liability is just. Full value of the chattel, resembling a forced sale.

Exam Tip

How serious was the interference? That is the bridge between the two torts.

2. Trespass to Chattels Requires Consequence

Impairment: the condition, quality, or value of the chattel is reduced. Substantial deprivation: the plaintiff loses use for a meaningful period, measured in context rather than by a fixed clock. Bodily or property harm: the interference causes injury to the plaintiff or another protected person or thing. Mere touching is not enough: unauthorized intermeddling without impairment, deprivation, or consequential harm may fail.

Key Takeaway

Unsolicited electronic messages that impaired the functioning and value of computer systems supported trespass to chattels. The theory depended on actual burden or impairment, not merely unwanted contact.

3. Conversion Requires Serious Interference

Conversion applies when the actor's dominion or control is so serious that justice may require payment of full value. Courts weigh the entire transaction.

Conversion factor What it asks

Extent and duration How complete and how long was the control?

Intent to assert an inconsistent right Did the defendant act like an owner rather than a temporary user?

Good faith Was the conduct an honest mistake or deliberate usurpation?

Harm to the chattel Was it destroyed, altered, damaged, or rendered unavailable?

Inconvenience and expense How severely did the interference burden the plaintiff?

4. Choosing Between the Claims

Short, harmless use

Often no tort unless the plaintiff proves impairment, substantial deprivation, or consequential injury.

Temporary damaging use

Trespass to chattels is the natural fit when the interference is real but not ownership-like.

Destruction or refusal to return

Conversion is likely because the interference effectively deprives the owner of the property.

Good-faith purchase from a wrongdoer

Good faith may matter to seriousness but does not always defeat conversion.

5. Copying Information Is Not Always Conversion

The outlines distinguish taking or controlling a chattel from merely copying information while leaving the original property available. Conversion ordinarily requires serious interference with the plaintiff's control of the thing itself.

Key Takeaway

Copying documents without taking or withholding the originals did not create the serious dominion over the physical documents required for conversion.

Key Takeaway

A coworker takes a laptop without permission during an important presentation, returns it six hours later, and corrupts the hard drive. The deprivation and impairment support trespass to chattels; destruction or a refusal to return could elevate the claim to conversion.

Common Mistake

Do not call every unauthorized use conversion. Conversion is reserved for serious interference; trespass to chattels itself requires a legally recognized consequence.

Primary Authorities

  • Restatement (Second) of Torts: trespass to chattels and conversion provisions.

  • CompuServe Inc. v. Cyber Promotions, Inc. (system impairment).

  • Pearson v. Dodd (copying without serious dominion).

  • Glidden v. Szybiak (interference and damage to a chattel).

Exam-ready conclusion

The two torts sit on a spectrum. Identify intentional interference, prove the required consequence, and use the seriousness factors to decide whether the defendant owes actual damages or the chattel's full value.