Markman v. Westview Instruments, Inc. is the Supreme Court decision that put claim construction — the interpretation of patent-claim language — in the judge's hands, not the jury's. Markman created the pretrial "Markman hearing" that shapes the rest of every patent case: the construction the judge issues often determines who wins on infringement and validity, before either side has called a single witness at trial.
Decided April 23, 1996, 517 U.S. 370.
Background
Herbert Markman owned U.S. Patent No. 4,550,246, which covered an inventory-tracking system for dry cleaners — a system to monitor garments through cleaning, pressing, and pickup using barcodes and reports. Westview Instruments sold a similar system. Markman sued for infringement. The dispute turned on the meaning of the word "inventory" in the patent claims.
The jury found the Westview system infringed Markman's claims. But the district court granted Westview's motion for judgment as a matter of law, ruling that the proper construction of "inventory" required tracking of cash flow as well as garments — something Westview's system didn't do.
The Federal Circuit affirmed en banc and articulated a sweeping rule: claim construction is a question of law for the judge, not a question of fact for the jury. Markman appealed the constitutional question — does the Seventh Amendment require a jury to determine claim meaning?
The holding
The Supreme Court unanimously affirmed. Justice Souter's opinion held:
[T]he construction of a patent, including terms of art within its claim, is exclusively within the province of the court.
The Court canvassed the historical record (the relevant period for Seventh Amendment purposes is 1791, when the Bill of Rights was ratified) and concluded that claim construction was either treated as a judge's task historically, or — where the practice was unclear — that judges were better positioned than juries to construe specialized technical language with consistency.
The "better positioning" rationale matters. Souter explicitly relied on it:
The construction of written instruments is one of those things that judges often do and are likely to do better than jurors unburdened by training in exegesis.
The Markman hearing
Markman created a procedure that is now universal in U.S. patent litigation — the Markman hearing, also called a claim construction hearing.
A typical Markman hearing:
- Disputed terms. The parties exchange lists of disputed claim terms and proposed constructions. Often 5–15 terms per case.
- Briefing. Each side files an opening brief explaining why its construction is correct, citing the claim language, specification, prosecution history, and (sometimes) extrinsic evidence like dictionaries and expert declarations.
- Hearing. The court holds an oral hearing — anywhere from a half-day to multi-day, depending on complexity. Some judges treat it as a tutorial on the technology; others run it like a motion hearing.
- Order. The court issues a written claim-construction order. The constructions in that order govern the rest of the case — infringement analysis, validity analysis, expert reports, jury instructions.
In most patent cases, the Markman ruling is the most consequential single decision the court makes. A construction that reads a key claim term broadly may decide infringement; a construction that reads a key term narrowly may avoid infringement entirely. Frequently both sides know how the case will end before any verdict is rendered.
Standard of review on appeal
Post-Markman, the Federal Circuit took claim-construction review de novo — appellate judges re-decided every claim-construction issue from scratch. (See Cybor Corp. v. FAS Technologies (Fed. Cir. 1998).) The result: claim constructions were reversed at high rates, undermining trial-court certainty.
In Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc. (2015), the Supreme Court added nuance: the ultimate construction is still a question of law, but subsidiary findings of historical fact (e.g., what extrinsic evidence said) get clear-error review. The pure-doctrinal portion remains de novo.
Practically, claim-construction reversals have moderated since Teva but remain common — a Federal Circuit appeal of an adverse Markman order is a real strategic option for both sides.
What it means for defendants
For a defendant in patent litigation, the Markman hearing is the most important strategic moment in the case after dispositive-motion practice:
- Identify the claim terms that decide your case. Most cases have one to three terms whose construction determines infringement or validity. Spend the bulk of the briefing on those.
- Read the claim language alongside the specification. Patent claim reading is the foundation. The specification supplies the meaning the inventor intended; the claim language constrains what was actually claimed.
- Use the prosecution history aggressively. Anything the patentee said to the PTO during prosecution — especially statements distinguishing prior art — narrows claim scope. (See Festo v. Shoketsu Kinzoku Kogyo for how prosecution amendments interact with the doctrine of equivalents.)
- Build a record on extrinsic evidence selectively. Dictionaries, treatises, and expert declarations help when the intrinsic record is ambiguous — but courts treat extrinsic evidence as supplementary, not primary.
A favorable Markman ruling can resolve a case before trial. An unfavorable one can be appealed de novo under Teva nuances — but a settlement is often more efficient than betting on Federal Circuit reversal.
Where the patent's core problem is § 101 ineligibility, claim construction interacts with the abstract-idea analysis: the Alice Step 1 inquiry depends on what the claim is "directed to," which depends in turn on what the claim language means. (See Alice Corp. v. CLS Bank.)
Bottom line
Markman is the structural decision that determines how every modern patent case unfolds. Claim construction is the judge's job; the Markman hearing is when the case gets decided in all but name. For defendants, getting claim construction right is more important than any other single litigation step except a § 101 motion. (US Patent 8,069,073 — the running example on this site — shows how a careful claim reading can isolate the abstract idea at the core of a software claim.)
Read the opinion: Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996).
This article is for general education and is not legal advice.