The Lapp Factors: How Interpace v. Lapp Built the Third Circuit's Confusion Test

When two companies used the Lapp name on non-competing electrical goods, the Third Circuit produced the ten-factor framework courts still use to gauge trademark confusion.

By Lidiia Levitska  ·  March 2, 2026
Coils of industrial electrical wire and ceramic insulators on a warehouse shelf
Identical marks on non-competing electrical goods forced the court to look past the names to the products themselves. Shutterstock
Educational content, not legal advice. This article explains general legal concepts. It does not create an attorney–client relationship. For your specific situation, consult a licensed attorney.

Trademark law gets hardest when two companies sell different things under the same name. That was the puzzle in Interpace Corp. v. Lapp, Inc., 721 F.2d 460 (3d Cir. 1983), where the plaintiff’s Lapp Division sold ceramic electrical insulators under the “Lapp” mark and the defendant, Lapp, Inc., sold electrical wire and cable under the very same word. The goods did not compete head to head, and the district court believed precedent forced it to dismiss. The Third Circuit reversed and, in doing so, put a ten-factor test for likelihood of confusion, drawn from its own earlier decision in Scott Paper Co. v. Scott’s Liquid Gold, Inc., 589 F.2d 1225 (3d Cir. 1978), at the center of the circuit’s analysis. Practitioners have called them the Lapp factors ever since.

At a glance

  • Case: Interpace Corp. v. Lapp, Inc., 721 F.2d 460 (3d Cir. 1983), No. 83-5036.
  • Court: U.S. Court of Appeals for the Third Circuit; panel of Circuit Judges Gibbons and Hunter and District Judge Mansmann (by designation).
  • Posture: Appeal from a bench-trial judgment dismissing the trademark-infringement complaint.
  • Holding: Likelihood of confusion can exist between non-competing goods; the court applied the ten factors it had set out in Scott Paper and reversed, remanding for entry of judgment for the mark owner and a proper remedy.
  • Significance: Made the ten-factor list the working Third Circuit likelihood-of-confusion test and clarified its application where the parties’ goods do not directly compete.

Same name, different wares

Interpace’s Lapp Division had long used “Lapp” on ceramic insulators; the defendant used “Lapp” on wire and cable. Both were electrical products sold to industrial buyers, but neither sold what the other did, and the district court found that the two customer pools had so far been predominantly distinct because American and European electrical components are built to different specifications and are not used together. After a bench trial, the district court made findings that largely favored the plaintiff yet felt compelled, by its reading of Scott Paper, to conclude that a plaintiff who had never entered the defendant’s market could not show the secondary meaning it thought the case required, and it dismissed. The Third Circuit disagreed, holding that proof of likelihood of confusion and proof of secondary meaning are indistinguishable in practice and that nothing in Scott Paper requires the senior user to have entered the junior user’s market. Where the parties deal in non-competing goods, the court explained, the analysis must look beyond the trademark to the nature of the products themselves and to the context in which they are marketed and sold.

Building the ten-factor test

To structure that inquiry the court set out the ten factors it had listed in Scott Paper: (1) the degree of similarity between the owner’s mark and the alleged infringing mark; (2) the strength of the owner’s mark; (3) the price of the goods and other indicia of buyer care and attention; (4) the length of time the defendant used the mark without evidence of actual confusion; (5) the defendant’s intent in adopting the mark; (6) evidence of actual confusion; (7) whether the goods, though non-competing, are marketed through the same channels and advertised through the same media; (8) the extent to which the parties’ sales targets overlap; (9) the relationship of the goods in consumers’ minds because of similarity of function; and (10) other facts suggesting the public might expect the prior owner to enter the defendant’s market. The Lapp opinion itself did not run a scorecard. It noted that the trial court had never formally applied the factors but had made findings in every relevant area, then worked through those findings factor by factor. Later Third Circuit decisions made the point explicit: the list is not exhaustive, no single factor controls, the factors carry different weight depending on the goods, and a finding of confusion does not require prevailing on a majority of them.

Why the marks “stand out” and the expansion factor

Applying the framework to the trial findings, the court recounted that the district court had determined the two marks were “for all practical purposes identical,” and that even when the defendant marketed its products under the “Lapp Cable” mark, “the name Lapp stands out.” The plaintiff’s mark was a strong one, built over more than fifty years of use on insulators. The shared trade channels weighed particularly heavily: both parties used the same methods of sale and both took space in the Thomas Register, the electrical industry’s major reference source. Sales targets were a closer call, because the district court found the parties’ customers had not yet been the same, but the defendant’s recent move into UL-rated wire and cable made future overlap likely. Insulators and wire were also functionally related, being basic electrical components often used together in more complex assemblies. The tenth factor, the likelihood that the owner would expand into the defendant’s field, proved pivotal. As the court put it, the likelihood-of-expansion factor is pivotal in non-competing products cases, because one of the chief reasons for protecting a mark owner in a market not his own is to protect his right someday to enter it. Here the plaintiff’s own confidential report showed actual plans to enter the wire and cable business, so the factor weighed heavily in favor of injunctive relief. The court reversed and remanded for entry of judgment for the mark owner and the fashioning of an appropriate remedy.

Open questions

  • How much weight does expansion deserve? Lapp made market-expansion central to non-competing-goods cases but left its weight relative to actual confusion to later panels.
  • When are trade channels “the same”? The court treated overlapping industrial buyers as significant, yet the line between shared and merely adjacent channels remains fact-bound.
  • Does the test differ for competing goods? Lapp arose with non-competing goods; subsequent decisions had to sort which factors recede when the parties compete directly.

Implications

  • Plead and prove the factors that fit. Because no factor is dispositive, focus evidence on the ones that matter for your goods, often similarity, strength, and the relationship of the products.
  • Watch the expansion factor. A senior user’s plausible plans to enter the junior user’s market can carry a non-competing-goods case.
  • Channels and buyers matter. Overlapping trade channels and shared customer targets bridge the gap between goods that are not direct substitutes.
  • Surname marks still signal source. Adding a descriptive term like “Cable” does not cure confusion when the distinctive surname dominates the impression.
  • Non-competition is not a defense. Defendants cannot rely on selling a different product; confusion as to source or affiliation suffices.

Frequently asked questions

What are the Lapp factors? They are the Third Circuit’s ten-factor test for likelihood of confusion: similarity of the marks; strength of the owner’s mark; the care and attention of buyers; how long the defendant used the mark without actual confusion; the defendant’s intent; evidence of actual confusion; whether the goods share trade channels and media; overlap in sales targets; the relationship of the goods in consumers’ minds; and whether the public would expect the owner to enter the defendant’s market.

Why did Interpace v. Lapp matter for non-competing goods? The district court found the facts favored the mark owner but read Scott Paper to require secondary meaning in the defendant’s market, which a plaintiff who had never sold there could never show, so it dismissed. The Third Circuit reversed, holding that proof of likelihood of confusion and proof of secondary meaning are indistinguishable in practice and that a mark owner need not enter the defendant’s market to prevail, with the relationship of the goods and the likelihood of market expansion doing much of the work.

Are all ten Lapp factors required to find confusion? No. The factors are a non-exhaustive checklist, not a scorecard. No single factor is dispositive, different factors carry different weight depending on the goods, and a court need not find a majority of them satisfied to find a likelihood of confusion.

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Lidiia Levitska
About the Author

Lidiia Levitska

International Intellectual Property Attorney

Lidiia Levitska focuses on intellectual property dispute resolution, policy, and advisory work across international institutions and government bodies. From 2021 to 2025 she served at the World Intellectual Property Organization (WIPO), managing arbitration cases and overseeing compliance with the Uniform Domain-Name Dispute-Resolution Policy (UDRP), and earlier led IP policy research as a Senior Policy Officer at the American Chamber of Commerce in Ukraine. She holds an LL.M. in International Intellectual Property Law from Chicago-Kent College of Law and an M.A. in Information Technology Law from the University of Tartu, and was admitted to the Ukrainian Bar in 2019.

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