Pleading and Proving Induced and Contributory Patent Infringement: A Practical Guide

Summary. This guide walks patentees and accused infringers through an induced or contributory patent infringement case in the order the work actually happens, from the pre-suit investigation and notice letter through pleading, infringement contentions, discovery, expert reports, summary judgment, jury instructions, and post-trial motions. Each step explains what must be proved under 35 U.S.C. § 271(b) and (c), what evidence carries the burden, which motions decide the issue, and what each side should file, say, or avoid. It covers the pleading standard after Twombly and Iqbal, the split over whether the complaint itself can supply knowledge, divided-infringement allegations after Akamai, the opinion-of-counsel election under 35 U.S.C. § 298, usage evidence and surveys on noninfringing uses, and the model jury instructions. A worked example follows a smart-thermostat dispute from the first letter to the verdict, with dates, decisions, and rough costs. Decision tables, common mistakes, and an FAQ close the guide.

A patent complaint often spends thirty pages on direct infringement and one paragraph on inducement, and that one paragraph is where many cases are lost. Accused vendors make the mirror-image mistake: they treat the inducement count as boilerplate until a technical writer's deposition shows that the company's help center walked customers through the claimed method, step by step, for three years after the notice letter arrived.

This guide is the procedural companion to Indirect and Divided Patent Infringement: Inducement, Contributory Liability, and the Akamai Problem, which explains the doctrine in depth. Here the focus is sequence: what to do first, what to file, what evidence to collect, and where each side's decisions get made.

The short answer

An indirect-infringement claim is won or lost on four facts: who directly infringed, when the defendant learned of the patent, what the defendant told people to do, and (for contributory claims) whether the accused feature has real uses that do not infringe.

If you represent the patentee:

1. Prove direct infringement by someone, with evidence of actual use rather than capability.
2. Create a knowledge record before suit, usually with a notice letter that identifies the patent and the accused product.
3. Plead facts, not statutory labels: the instructions, marketing, design choices, and contract terms that encourage the infringing use.
4. For contributory claims, define the "component" as the separable feature and gather data showing it has no substantial noninfringing use.
5. Use the model jury instructions and a special verdict form that separates theories and time periods.

If you represent the accused infringer:

1. Attack the predicate: no proof that any identified person performed every step.
2. Pin down the first-knowledge date, because it caps damages for inducement and contributory infringement.
3. Form and document a good-faith noninfringement position early, and decide deliberately whether to rely on an opinion of counsel.
4. Prove noninfringing uses with usage data or surveys, not adjectives.
5. Preserve every judgment-as-a-matter-of-law argument with a timely motion under Rule 50(a).

What you will have to prove

Every indirect claim under 35 U.S.C. § 271 has its own elements, and the patentee bears the burden on all of them by a preponderance of the evidence.

Two corollaries shape the whole case. Intent may be proved circumstantially, Water Technologies Corp. v. Calco, Ltd., 850 F.2d 660 (Fed. Cir. 1988), but it must be intent to cause infringement, not just intent to cause the acts, Manville Sales Corp. v. Paramount Systems, Inc., 917 F.2d 544 (Fed. Cir. 1990); DSU Medical Corp. v. JMS Co., 471 F.3d 1293 (Fed. Cir. 2006) (en banc in relevant part). And the patentee may prove inducement of a class of direct infringers, such as all customers, rather than individual acts, provided it proves that infringement occurred. Dynacore Holdings Corp. v. U.S. Philips Corp., 363 F.3d 1263 (Fed. Cir. 2004).

Phase 1: Before the case is filed

Step 1: Chart the claims by actor (both sides)

Before anyone charts the claims against a product, chart them against people. For each claim element or method step, write down who performs it in the real world: the accused company, its customers, a cloud host, a contract manufacturer, a physician, a patient. The answer tells you which theories are available.

• If one entity performs everything, you may not need indirect theories at all.
• If customers perform every step of a method, customers are direct infringers and the vendor's exposure is inducement or contributory infringement.
• If steps are split between the vendor and customers, the patentee needs attribution under Akamai (direct infringement by the vendor) or a single customer who performs or is responsible for every step; inducement alone will not work.
• If the claim is to a system, ask who puts the system into service, controlling and benefiting from each element. Centillion Data Systems, LLC v. Qwest Communications International, Inc., 631 F.3d 1279 (Fed. Cir. 2011); Intellectual Ventures I LLC v. Motorola Mobility LLC, 870 F.3d 1320 (Fed. Cir. 2017).

Accused infringers should do the same exercise the day a letter arrives; it identifies the claim terms that will decide who acts ("user," "client device," "configured to") and the documents that will matter.

Step 2: Find the direct infringer and the proof of actual use

The patentee's pre-filing investigation under Fed. R. Civ. P. 11 should produce evidence that someone actually practices the claim, not merely that the product could. Sources, roughly in order of strength:

1. The defendant's own statements that customers use the feature (case studies, earnings calls, adoption metrics, release notes).
2. Default settings and mandatory workflows that make the claimed operation automatic.
3. Industry standards that require, rather than permit, the claimed behavior. Compliance with a mandatory section can prove infringement; an optional section requires proof that someone actually used it. Fujitsu Ltd. v. Netgear Inc., 620 F.3d 1321 (Fed. Cir. 2010).
4. Public user forums, support articles, and videos showing the claimed use.
5. Test purchases and controlled testing (useful for showing how the product works, weak as proof of what customers do).

The Federal Circuit accepts circumstantial proof of direct infringement, as in Lucent Technologies, Inc. v. Gateway, Inc., 580 F.3d 1301 (Fed. Cir. 2009), but rejects evidence that shows only capability, as in ACCO Brands, Inc. v. ABA Locks Manufacturer Co., 501 F.3d 1307 (Fed. Cir. 2007).

Step 3: Decide whether, when, and how to give notice (patentee)

A pre-suit letter is usually worth sending, because it does three jobs: it establishes knowledge for § 271(b) and (c) and starts the willfulness clock; if it identifies the patent and charges a specific product, it provides actual notice under 35 U.S.C. § 287(a), Amsted Industries Inc. v. Buckeye Steel Castings Co., 24 F.3d 178 (Fed. Cir. 1994); and it avoids the argument, accepted in some districts, that the complaint cannot supply the knowledge element for claims in the same suit.

The cost is declaratory judgment exposure. Under MedImmune, Inc. v. Genentech, Inc., 549 U.S. 118 (2007), the question is whether all the circumstances show a real and immediate controversy, and letters that identify a patent and a product and set short deadlines usually do. Hewlett-Packard Co. v. Acceleron LLC, 587 F.3d 1358 (Fed. Cir. 2009). Patentees who care most about forum often send the letter the same day they file, or file first and send a courtesy copy, accepting that in courts following the Delaware rule described in Step 5 a letter delivered a day or two before suit will not supply pre-suit knowledge. A letter should contain:

• the patent number and representative claims;
• the specific accused products and features, by name and version;
• a claim chart or a clear description of how the product meets the claims, citing the recipient's own manuals and marketing;
• a description of the customers' use, if inducement is the theory;
• a response date that is reasonable (two to four weeks is typical); and
• a reservation of rights.

Avoid statements you cannot support; many states regulate bad-faith assertion letters, and the letter will be an exhibit. Templates appear in the Indirect Infringement Toolkit: Knowledge Evidence, Direction or Control Proof, and Substantial Noninfringing Use Analyses, and the general mechanics in Drafting a Demand Letter: A Practical Checklist.

Step 4: Triage the letter (accused infringer)

The day the letter arrives is the first day of potential inducement liability, so the recipient's first week matters more than most of the case.

1. Preserve. Issue a litigation hold covering product, documentation, support, sales, and telemetry systems. See Litigation Hold and Evidence Preservation Checklist: A Practical Checklist.
2. Route the letter to counsel, not engineering. Internal emails speculating about infringement become trial exhibits.
3. Calendar the IPR clock. A petition for inter partes review must be filed within one year of service of a complaint, and filing a declaratory judgment action that challenges validity first bars the petition. 35 U.S.C. § 315.
4. Commission a noninfringement analysis. Under Commil, a reasonable belief in noninfringement can negate intent; a belief in invalidity cannot. A written opinion from competent counsel, based on complete facts, is the strongest form.
5. Review the instructions. Decide whether help-center pages, onboarding materials, and default settings that walk customers into the claimed configuration should change. A prompt, documented change after notice reads well on intent and willfulness.
6. Check indemnities in both directions. Customer agreements may obligate you to defend customers; supplier agreements may let you tender to your own vendors.
7. Decide on a response. Options range from a request for claim charts to a declaratory judgment action under 28 U.S.C. § 2201. See Responding to a Cease and Desist Letter: A Practical Guide and Filing or Defending a Declaratory Judgment Action: A Practical Guide.

Phase 2: The complaint and the first motion

Step 5: Draft the indirect-infringement counts (patentee)

Fed. R. Civ. P. 8(a)(2), as interpreted in Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007), and Ashcroft v. Iqbal, 556 U.S. 662 (2009), requires facts that make each element plausible. For indirect claims the Federal Circuit applied that standard even when the old form complaint governed direct infringement, and the form is gone now. Draft each count element by element:

Inducement.

1. Direct infringement. Identify the direct infringers by class (customers, end users, physicians, distributors) and what they do, with citations to the defendant's materials showing the use.
2. Knowledge of the patent. Plead the date and source: the notice letter (attach it or quote it), earlier litigation on the patent or its family, the defendant's citation of the patent in its own prosecution, licensing discussions, standard-setting declarations, or employees who came from the patentee. In Lifetime Industries, Inc. v. Trim-Lok, Inc., 869 F.3d 1372 (Fed. Cir. 2017), allegations that the defendant hired two of the patentee's former employees who knew of the patent helped carry the pleading.
3. Knowledge of infringement and specific intent. Quote the instructions, tutorials, marketing, and configuration guides that tell users to perform the claimed steps. Explain why following them infringes.
4. Active steps and causation. Tie the materials to the users' conduct: the instructions are distributed with the product, the defaults are set by the defendant, the support staff walk customers through it.

In re Bill of Lading Transmission & Processing System Patent Litigation, 681 F.3d 1323 (Fed. Cir. 2012), is the model: complaints built from the defendants' own websites and advertising stated a plausible inducement claim. Superior Industries, LLC v. Thor Global Enterprises Ltd., 700 F.3d 1287 (Fed. Cir. 2012), is the counterexample: no facts about intent, no claim.

Knowledge and the complaint-as-notice split. If you have pre-suit knowledge facts, plead them, and plead post-filing knowledge separately in the alternative. If you do not, check the assigned judge. Some courts hold that the complaint cannot supply knowledge for claims in the same suit (the Delaware rule of ZapFraud, Inc. v. Barracuda Networks, Inc., 528 F. Supp. 3d 247 (D. Del. 2021)); others allow post-filing claims (for example, RightQuestion, LLC v. Samsung Electronics Co., 2022 WL 507487 (E.D. Tex. 2022)). The Western District of Texas has often dismissed pre-suit claims without prejudice and allowed repleading once fact discovery opens. A willful-blindness theory needs specific facts; one court held that a policy against reading competitors' patents, standing alone, was not enough to plead it. USC IP Partnership, L.P. v. Facebook, Inc., 2021 WL 3134260 (W.D. Tex. 2021).

Contributory infringement. Identify the component at the feature level (a firmware module, a software tool, a specific chemical, a replacement part), explain why it is especially made or adapted for the claimed use, and plead facts showing that it has no substantial noninfringing use. Do not describe other uses of the accused product in your own complaint unless you also explain why they do not count; in Bill of Lading, the patentee's description of the products' other functions defeated its contributory claims at the pleading stage, and conclusory recitals of the statute fared no better in Sonos, Inc. v. Google LLC, 2022 WL 799367 (N.D. Cal. 2022).

Divided infringement. Plead the facts that make the other actor's steps attributable: the contract terms, the conditions on access or benefits, and the defendant's control over the manner or timing of the steps. A bare allegation of "direction or control" was dismissed in Lyda v. CBS Corp., 838 F.3d 1331 (Fed. Cir. 2016); specific allegations about the defendants' own pilot-scale and full-scale testing survived in Nalco Co. v. Chem-Mod, LLC, 883 F.3d 1337 (Fed. Cir. 2018).

Label-based inducement. In Hatch-Waxman cases the label is the instruction manual. Quote the label sections that describe the claimed use, and plead any promotional statements (press releases, product catalogs, sales materials) that point prescribers toward a carved-out use, because the skinny-label decisions read the label and the marketing together. That body of law has moved quickly since 2021, so check the current status of the cases discussed in the companion article before relying on them; the litigation mechanics are in Running an ANDA Litigation: A Practical Guide.

Detail and restraint. The required detail rises with the complexity of the technology and the materiality of the disputed element, and a complaint can plead facts that defeat its own theory. Bot M8 LLC v. Sony Corp. of America, 4 F.4th 1342 (Fed. Cir. 2021). For simple products, photographs and a comparison to the claims may be enough. Disc Disease Solutions Inc. v. VGH Solutions, Inc., 888 F.3d 1256 (Fed. Cir. 2018). The general drafting approach is covered in Drafting a Complaint That Survives a Motion to Dismiss.

Step 6: Move to dismiss, or defend the pleading

A Rule 12(b)(6) motion is due within 21 days of service unless the defendant waived service or obtained an extension. Defendants typically target four things: missing knowledge facts (especially pre-suit), conclusory intent allegations, contributory claims whose "component" obviously has other uses, and divided-infringement theories without conditioning facts. Two realities temper the decision:

• Most dismissals of indirect claims are without prejudice. Rule 15(a) leave to amend is freely given, so a win often buys only a narrower complaint and a few months.
• Arguments that depend on claim construction do not belong in a Rule 12 motion. Nalco reversed a dismissal that rested on the district court's reading of "flue gas" and "injecting."

A partial motion aimed at pre-suit inducement and willfulness is often the best value for a defendant in a district that follows ZapFraud: it can eliminate the most expensive damages period until discovery produces real knowledge facts. A patentee facing such a motion should consider amending once, promptly, rather than litigating a thin complaint. Typical cost for a fully briefed motion runs from the low tens of thousands to around $100,000 per side. See Motions to Dismiss Under Rule 12: A Practical Guide for Plaintiffs and Defendants.

Step 7: Answer, defenses, and counterclaims (accused infringer)

The answer should deny the knowledge and intent allegations with precision (admitting the date of a letter is not admitting knowledge of infringement) and plead the defenses that are specific to indirect claims:

• noninfringement, including no direct infringement by anyone;
• invalidity under 35 U.S.C. § 282, with counterclaims for declaratory judgment of noninfringement and invalidity;
• exhaustion and license (including implied license from the patentee's own sales);
• the six-year damages limit of 35 U.S.C. § 286 and failure to mark under § 287, which requires the accused infringer to identify the unmarked products it contends practice the claims, after which the patentee must prove compliance, Arctic Cat Inc. v. Bombardier Recreational Products Inc., 876 F.3d 1350 (Fed. Cir. 2017);
• government use under 28 U.S.C. § 1498, prosecution history estoppel, and equitable defenses where the facts support them.

Courts disagree about whether affirmative defenses must meet the Twombly standard, so plead facts where you have them. See Drafting an Answer and Affirmative Defenses: A Practical Guide. If customers have been sued separately, this is also the moment to seek a stay of the customer cases under the customer-suit exception, In re Nintendo Co., 756 F.3d 1363 (Fed. Cir. 2014), recognizing that the exception applies only where the manufacturer's case will resolve the major issues, Spread Spectrum Screening LLC v. Eastman Kodak Co., 657 F.3d 1349 (Fed. Cir. 2011).

Phase 3: Contentions and claim construction

Step 8: Serve and test infringement contentions

Districts with local patent rules require infringement contentions soon after the case management conference, and the rules ask specifically about indirect infringement. The Northern District of California's Patent L.R. 3-1(d), for example, requires, for each claim alleged to be indirectly infringed, an identification of any direct infringement and a description of the acts of the alleged indirect infringer that contribute to or induce it, and, where direct infringement rests on the joint acts of multiple parties, a description of each party's role. The Eastern District of Texas rule is similar, and courts without local rules usually impose comparable requirements in the scheduling order under Fed. R. Civ. P. 16.

For the patentee, contentions are the first binding statement of theory, and amendments usually require good cause. Identify every category of direct infringer, every inducing act by document, and, for divided theories, the conditioning and manner-or-timing facts. For the accused infringer, deficient contentions are leverage: a motion to compel more specific contentions or to strike undisclosed theories narrows the case cheaply. Serve noninfringement contentions that put the predicate at issue early ("Plaintiff identifies no person who performs step (c)").

Step 9: Construe the terms that decide who acts

Claim construction often decides indirect cases without anyone saying so. Terms that identify the actor ("user," "client," "server," "receiving at"), the location ("on the client device"), or the timing ("during the event") determine whether one actor performs every step or the claim is divided. Terms that describe capability ("configured to," "operable to") rather than actual operation affect whether a product infringes when sold or only when used, which in turn decides whether direct or indirect theories are needed.

Both sides should list these terms when they exchange proposed constructions, and accused inducers should remember that a reasonable claim reading formed before suit supports a good-faith defense even if the court ultimately adopts a different construction. For the hearing itself, see Preparing for a Markman Hearing: A Practical Guide and the Claim Construction Toolkit: Charts, Briefs, Expert Declarations, and Hearing Materials.

Phase 4: Fact discovery

Fact discovery in an indirect case has one organizing principle: every request should help prove or disprove an element in the table above. A patentee that serves the standard sixty-request set and waits usually learns at summary judgment that it has thousands of pages about how the product works and nothing about who actually used it.

Step 10: Prove actual use, knowledge, and intent (patentee)

Write the discovery plan backward from the cases that end indirect claims. In E-Pass Technologies, Inc. v. 3Com Corp., 473 F.3d 1213 (Fed. Cir. 2007), manual excerpts that taught each step of a method in isolation, for general-purpose handheld devices, did not show that any customer performed the method, and the court observed that if infringing use were really everywhere, the patentee should have had no trouble producing testimony from even one user. Mirror Worlds, LLC v. Apple Inc., 692 F.3d 1351 (Fed. Cir. 2012), applied the same rule to a trial record: an expert who described what the software could do, plus manuals, reviews, and surveys never tied together step by step, did not prove inducement. The contrast is Moleculon Research Corp. v. CBS, Inc., 793 F.2d 1261 (Fed. Cir. 1986), where extensive sales of a puzzle, an instruction sheet teaching the claimed solution, and a solution booklet supported the finding, because the product had essentially one use and the instructions taught it.

Four tactics separate the cases that reach a jury from the ones that do not.

1. Make the defendant count for you. Ask by interrogatory how many customers enabled the feature, when, and in what configuration. In i4i Ltd. Partnership v. Microsoft Corp., 598 F.3d 831 (Fed. Cir. 2010), a joint stipulation and Microsoft's own interrogatory answers confirming that Word was used to open, edit, and save custom XML documents, together with expert testimony that those uses infringed, established direct infringement, and Microsoft's usage data and a marketing document listing real customer uses helped prove that customers used the feature.
2. Lock down the instructions. Serve requests for admission under Fed. R. Civ. P. 36 to authenticate each version of the help pages and fix its publication dates; an admitted matter is conclusively established unless the court allows withdrawal. The defendant's manuals and marketing are its own statements and come in against it under Fed. R. Evid. 801(d)(2).
3. Find one real user early. Subpoena a few cooperative customers with narrow requests that respect the nonparty-burden limits of Rule 45(d). One homeowner, physician, or IT administrator who testifies to following the defendant's setup guide is worth a terabyte of logs. Telemetry is the other half of the proof and the most perishable; ask for retention schedules in the first week and negotiate the production format in the ESI protocol (see Negotiating an ESI Protocol and Managing E-Discovery Costs). At trial, the data comes in through a summary under Fed. R. Evid. 1006, with the underlying records made available to the other side.
4. Amend contentions as soon as discovery changes the theory. Good cause to amend under local patent rules requires diligence, and the Federal Circuit upheld a finding that a delay of nearly three months after the key deposition showed none. O2 Micro International Ltd. v. Monolithic Power Systems, Inc., 467 F.3d 1355 (Fed. Cir. 2006).

The mechanics of each tool are covered in A Practical Discovery Refresher: Mastering the Tools, Rules, and Pitfalls of Federal Civil Litigation, and customers on the receiving end of a subpoena should read Responding to a Third-Party Subpoena: A Practical Guide for Businesses.

Step 11: Build the good-faith and noninfringing-use record (accused infringer)

The accused infringer has to prove a state of mind and a usage pattern, and both are easier to prove with documents created before anyone sued.

1. Fix the good-faith story in writing. Identify who evaluated the patent, when, on what facts, and what the company did next. In Vita-Mix Corp. v. Basic Holding, Inc., 581 F.3d 1317 (Fed. Cir. 2009), original instructions that taught a use the defendant could reasonably believe was noninfringing did not show intent, and instructions amended before suit to teach an undisputedly noninfringing use evidenced an intent to discourage infringement. That is the template: a reasoned position, followed by conduct consistent with it.
2. Make the opinion-of-counsel election deliberately, and on time. Local rules force the decision. In the Northern District of California, a party relying on advice of counsel must produce the opinion and the related materials covered by the waiver within 30 days after the claim construction ruling (Patent L.R. 3-7); in the Eastern District of Texas, the docket control order sets the date (P.R. 3-7); and under both rules a party that misses the deadline may not rely on the advice absent a court order or stipulation. Reliance waives privilege over communications on the same subject, including work product communicated to the client, In re EchoStar Communications Corp., 448 F.3d 1294 (Fed. Cir. 2006), but ordinarily not over trial counsel's files, In re Seagate Technology, LLC, 497 F.3d 1360 (Fed. Cir. 2007) (en banc). A Fed. R. Evid. 502 order limits the collateral damage. If you decide not to rely, 35 U.S.C. § 298 bars the patentee from using that choice, or the absence of any opinion, to prove willfulness or intent to induce.
3. Build your own usage proof. The patentee bears the burden of proving that noninfringing uses are not substantial, Golden Blount, Inc. v. Robert H. Peterson Co., 438 F.3d 1354 (Fed. Cir. 2006), but the defendant usually owns the data that decides the question. Preserve telemetry by mode and configuration, and have counsel analyze it before production so the first time you learn what it shows is not in the patentee's expert report.
4. Coordinate with customers. Customers will be subpoenaed, and some will tender indemnity claims. A written common-interest agreement lets counsel share defense analysis without waiving privilege; see Attorney-Client Privilege and Work Product for Businesses: Upjohn, In-House Counsel, and the Common Interest.
5. Protect customer data on the way out. Usage logs often contain personal information and customers' confidential business data. Negotiate a two-tier protective order before producing them, as described in Negotiating a Protective Order and Filing Under Seal: A Practical Guide.

Step 12: Take and defend the depositions that decide intent

For the patentee, the most valuable witnesses are rarely the engineers. They are the person who received the notice letter, the product manager who chose the feature's default, the technical writer who drafted the setup guide, the support lead whose team walked customers through configuration, and the analyst who tracks feature adoption. A Rule 30(b)(6) notice should cover at least:

• the date, source, and internal circulation of the company's first knowledge of the patent and its family;
• every evaluation of the patent the company intends to rely on at trial;
• the authorship, approval, versions, and distribution of instructions, tutorials, and in-product prompts for the accused feature;
• the feature's default settings and the reasons for each change;
• the metrics the company keeps on how customers use the feature, and what they show;
• design-around work and every change made after notice; and
• for divided claims, the conditions customers must satisfy to use the service and how the company enforces them.

For the accused infringer, preparation matters more than usual because the questions go to state of mind. Witnesses should know the timeline cold, describe what they did and why, and decline to guess about what customers do. Guesses are evidence. In Cross Medical Products, Inc. v. Medtronic Sofamor Danek, Inc., 424 F.3d 1293 (Fed. Cir. 2005), an employee's deposition answer that he was "sure some surgeons do that," read with a surgeon's declaration that contact with bone sometimes occurred incidentally, created a genuine dispute about whether surgeons made the claimed apparatus. Expect questions aimed at willful blindness under Global-Tech ("Did anyone read the patent? Why not?"), and prepare the witness to explain the company's actual process for evaluating third-party patents. See Preparing and Defending a Rule 30(b)(6) Deposition.

Phase 5: Expert reports

Step 13: Move the technical expert from capability to actual use

Under Fed. R. Civ. P. 26(a)(2)(B), the report must state every opinion and its basis, and opinions left out are usually excluded under Rule 37(c)(1). In an indirect case the infringement report has three jobs.

1. Map the instructions to the steps, together and in order. A chart pairing each claim step with the help article, video, or prompt that produces it is the answer to E-Pass. Where the defendant designed the product for the infringing use and recommended that use, a jury may find direct infringement, Toshiba Corp. v. Imation Corp., 681 F.3d 1358 (Fed. Cir. 2012); in Lucent, instructions, extensive sales, and the expert's testimony that he, his wife, and likely others used the method were described as "barely sufficient."
2. Identify actual users. Cite telemetry, customer testimony, support tickets, and admissions. The expert's own testing shows only that the product can infringe.
3. Stay out of the defendant's head. Fed. R. Evid. 702 requires the proponent to show that each opinion is more likely than not reliable, and courts routinely exclude experts who narrate the defendant's emails or opine on what it intended. The expert may explain what the instructions teach and why following them infringes; the jury decides intent.

For divided claims, the report should name the actor for each step and marshal the conditioning and manner-or-timing facts. Whether one actor directed or controlled another is a question of fact under Akamai, which is why a well-supported report often keeps attribution away from summary judgment. Deposition strategy for both sides is in Taking and Defending an Expert Deposition: A Practical Guide.

Step 14: Commission usage surveys and telemetry analyses (both sides)

Usage evidence does two different jobs, and confusing them loses cases. Evidence of how often customers use the infringing mode proves direct infringement and sizes the royalty base. Evidence of how often, how practically, and for what purposes customers use the noninfringing modes decides contributory infringement. In Vita-Mix, the court held that the trial judge erred in striking a survey that observed some users leaving the stir stick in place without stirring, because its limitations went to weight rather than admissibility, but it also noted that a survey measuring the frequency of infringing use said nothing about whether the noninfringing use was substantial.

• Prefer logs to surveys when logs exist. Telemetry measures behavior rather than memory. Disclose the queries, and present the results through a Rule 1006 summary.
• Survey the right universe, about behavior. Ask actual purchasers or users in the damages period what they did, not whether they infringed, and offer "don't know" answers. The i4i survey went to 988 businesses, drew 46 responses, and counted every nonresponder as noninfringing; that conservative assumption helped it survive a Rule 403 challenge, and the court held it properly admitted over a hearsay objection under Fed. R. Evid. 703 because the damages expert relied on it.
• Frame the component before you count. A feature inside a larger product can be the relevant "material or apparatus" when it is separate and distinct, for example because it can be left out of or added to the product (i4i; Ricoh Co. v. Quanta Computer Inc., 550 F.3d 1325 (Fed. Cir. 2008)). Features that define the product and serve its noninfringing use are not separable (Vita-Mix). A defense survey must measure uses of the same component the patentee accuses.
• Measure substantiality, not just frequency. The jury may weigh a use's frequency, its practicality, the invention's intended purpose, and the intended market (i4i); uses that are "unusual, far-fetched, illusory, impractical, occasional, aberrant, or experimental" do not count (Vita-Mix); and recommending one use over another does not make the other insubstantial (Toshiba).

A patentee with the burden and no data loses. Toshiba's contributory claim failed on summary judgment because it offered no survey, expert, or other evidence of how often users chose the noninfringing mode. Survey design principles carry over from trademark practice; see Consumer Survey Expert Methodology in Trademark Cases: A Practical Guide and Shari Seidman Diamond, Reference Guide on Survey Research, in Federal Judicial Center, Reference Manual on Scientific Evidence (3d ed. 2011). A defensible usage survey typically costs $75,000 to $200,000 including the expert's report and deposition.

Step 15: Start the damages clock at knowledge

35 U.S.C. § 284 promises damages adequate to compensate for the infringement, and for an indirect infringer the infringement starts at knowledge (Aro II). The damages model therefore needs a date and a count: infringing uses or units after the knowledge date, tied to the acts the defendant induced or contributed to. Royalties on noninfringing activity fail. In Enplas Display Device Corp. v. Seoul Semiconductor Co., 909 F.3d 398 (Fed. Cir. 2018), the court affirmed the inducement verdict but vacated a $4 million award because the expert's royalty base consisted of sales of lenses that were neither accused nor shown to infringe. Build alternative calculations for each disputed knowledge date (an earlier willful-blindness date, the letter, the complaint, the claim construction ruling) and for each theory, so the verdict form can track them. Apportionment and the Georgia-Pacific royalty factors are covered in Proving and Attacking Patent Damages: A Practical Guide and the Patent Damages Toolkit: Royalty Models, Expert Reports, and Daubert Motions.

Phase 6: Summary judgment and Daubert

Step 16: Move for, or survive, summary judgment

Under Fed. R. Civ. P. 56, a defendant may win by showing that the patentee lacks evidence on an element it must prove at trial, Celotex Corp. v. Catrett, 477 U.S. 317 (1986), and the patentee survives by pointing to evidence from which a reasonable jury could find for it, Anderson v. Liberty Lobby, Inc., 477 U.S. 242 (1986). Indirect claims offer more targets than most.

Three lessons recur. First, substantial noninfringing uses defeat only contributory claims; § 271(b) has no such requirement, Erbe Elektromedizin GmbH v. Canady Technology LLC, 629 F.3d 1278 (Fed. Cir. 2010), and Toshiba vacated a summary judgment that held otherwise. Second, intent rarely goes away on summary judgment, so the defendant's best investment is usually a partial motion: no pre-notice damages, no contributory claim, no divided theory. Pair it with Daubert challenges to the survey or the damages model under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) and Rule 702; see Expert Witnesses After the 2023 Amendment to Rule 702: Daubert, Disclosure, and Cross-Examination. Third, a defendant that loses a fact-bound motion must preserve the issue at trial, because an order denying summary judgment cannot be appealed after a full trial on the merits, Ortiz v. Jordan, 562 U.S. 180 (2011) (purely legal issues decided at summary judgment are preserved without a post-trial motion, Dupree v. Younger, 598 U.S. 729 (2023), but sufficiency arguments about knowledge, intent, and use are factual). Budget $150,000 to $400,000 per side for summary judgment and Daubert briefing in a mid-sized case. The general practice is covered in Summary Judgment Under Rule 56: Winning and Surviving Before Trial.

Phase 7: Trial

Step 17: Settle the jury instructions and the verdict form early

Start from model language. The Federal Circuit Bar Association's Model Patent Jury Instructions address inducement, contributory infringement, divided infringement, and willfulness (Nos. 3.2, 3.3, 3.7, and 3.10 in recent editions; the numbering shifts, so cite the edition), and the AIPLA and Northern District of California models are the usual alternatives. Creativity is expensive. In Power Integrations, Inc. v. Fairchild Semiconductor International, Inc., 843 F.3d 1315 (Fed. Cir. 2016), the district court gave an instruction, largely tracking the patentee's proposal, stating that the infringement "need not have been actually caused" by the defendant's actions; because inducement requires actual, successful inducement of a direct infringer, the Federal Circuit vacated the verdict. Instructional error requires a new trial only when the instruction was legally erroneous and prejudicial, Ericsson, Inc. v. D-Link Systems, Inc., 773 F.3d 1201 (Fed. Cir. 2014), and the inducement case in Power Integrations was close enough that the error mattered. The charge-conference fights in indirect cases are predictable:

• Willful blindness. The patentee wants the instruction; it is proper only with evidence of both Global-Tech elements, a subjective belief in a high probability that the fact exists and deliberate actions to avoid learning it.
• Good faith. The accused inducer wants the jury told that inducement requires knowledge that the induced acts infringe, so that a reasonable, honestly held reading of the claims negates intent; the patentee wants the jury told that a belief in invalidity does not (Commil). Both are correct statements of law, and both usually belong in the charge.
• Opinion of counsel. A defendant that does not rely on an opinion should request an instruction implementing § 298, so the jury draws no inference from its absence.
• Causation. Track the model language that the defendant's acts actually induced the direct infringement.

Under Fed. R. Civ. P. 49, ask for a special verdict that separates each patent and claim, direct infringement by the identified class, inducement, contributory infringement, willfulness (reached only if infringement is found), and damages by theory and by period (before and after the letter, and if it matters, after the claim construction ruling). Separate answers turn a damages error into a recalculation instead of a retrial. Preserve objections under Fed. R. Civ. P. 51: object on the record, stating distinctly the matter and the grounds, at the opportunity the court provides before instructions and arguments are delivered; otherwise review is limited to plain error. Fairchild preserved its challenge by doing exactly that. Charge and verdict-form templates appear in the Jury Trial Toolkit: Voir Dire, Openings, Exhibits, and Instructions.

Step 18: Try knowledge and intent with documents, a timeline, and one real user

Patentee. Juries decide intent from sequence. Build a timeline demonstrative that puts the letter date next to every later version of the instructions, every adoption metric, and every decision not to change course. Call one or two actual users, live or by designated deposition testimony (see Designating and Playing Deposition Testimony at Trial: A Practical Guide), and use the defendant's own instructions as the script for the direct-infringement case.

Accused infringer. Tell the good-faith story through the people who lived it: the engineer or lawyer who evaluated the patent, the opinion author if you rely on the opinion, and the product manager who changed the default after notice. Keep the technical defense inside the court's claim construction, because experts may not argue construction to the jury.

Motions in limine (both sides). Under § 298 and Rule 403, exclude argument that the defendant failed to obtain or produce an opinion; exclude expert testimony about the defendant's state of mind; and exclude references to dismissed theories (a contributory claim lost on summary judgment, for example) unless they bear on a live issue.

Phase 8: Post-trial

Step 19: Test the verdict under Rules 50 and 59

Move under Fed. R. Civ. P. 50(a) before the case goes to the jury, specifying the judgment sought and the law and facts that support it, and renew under Rule 50(b) no later than 28 days after entry of judgment, joined with any request for a new trial under Fed. R. Civ. P. 59, which has the same deadline. Skip the renewed motion and the court of appeals cannot order judgment or a new trial on sufficiency grounds. Unitherm Food Systems, Inc. v. Swift-Eckrich, Inc., 546 U.S. 394 (2006). The regional circuit's standard governs, and the court reviews the whole record, drawing inferences for the verdict winner and disregarding evidence favoring the movant that the jury was not required to believe. Reeves v. Sanderson Plumbing Products, Inc., 530 U.S. 133 (2000).

The cases show where indirect verdicts break, and where they hold:

• The direct-infringement predicate breaks most often. After winning the intent question in the Supreme Court, Commil lost on remand because substantial evidence did not show that Cisco's devices, when used, performed the claimed "running" step, which defeated both its direct and its inducement theories. Commil USA, LLC v. Cisco Systems, Inc., 813 F.3d 994 (Fed. Cir. 2015). In Mirror Worlds, the district court granted judgment as a matter of law of no inducement at the close of the patentee's evidence, and the Federal Circuit affirmed.
• Instruction errors produce new trials, not judgments. Power Integrations vacated the inducement verdict but declined to enter judgment for the defendant, because the record did not require a finding of no inducement as a matter of law.
• Intent findings usually survive. Enplas affirmed the denial of judgment on inducement while calling it a close question, and i4i upheld findings of knowledge and intent built on the defendant's emails, training materials, and support resources.
• Damages tied to the wrong activity fall. Enplas is the example, and Lucent vacated a lump sum the evidence did not connect to the infringing feature.

The procedure is covered in Filing or Opposing Post-Trial Motions Under Rules 50, 59, and 60: A Practical Guide.

Step 20: Willfulness, enhancement, fees, and injunctions

Willfulness is a jury question, and knowledge of the patent is a prerequisite, WBIP, LLC v. Kohler Co., 829 F.3d 1317 (Fed. Cir. 2016), where the court noted that Kohler did not contest its pre-suit knowledge and had admitted it in its own summary judgment papers, a reminder to draft statements of undisputed fact with trial in mind. The jury asks whether the infringement was deliberate or intentional, Eko Brands, LLC v. Adrian Rivera Maynez Enterprises, Inc., 946 F.3d 1367 (Fed. Cir. 2020); the judge then decides whether to enhance, up to three times, in egregious cases under Halo Electronics, Inc. v. Pulse Electronics, Inc., 579 U.S. 93 (2016), usually by working through the factors in Read Corp. v. Portec, Inc., 970 F.2d 816 (Fed. Cir. 1992). Fees under 35 U.S.C. § 285 follow the exceptional-case standard of Octane Fitness, LLC v. ICON Health & Fitness, Inc., 572 U.S. 545 (2014). An injunction requires the four-factor showing of eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006), and against an inducer it is usually aimed at conduct rather than existing users: the i4i injunction barred Microsoft from selling Word with the infringing editor and from instructing or assisting new customers in its use, while leaving customers who already had the product alone.

Worked example: a smart-thermostat dispute from letter to verdict

Ambrose Thermal LLC owns a patent claiming a method of setting back a home thermostat: (a) detecting that the last occupant's phone has left a geofence around the home, (b) computing a predicted return time from the household's stored occupancy history, (c) setting back the temperature, and (d) restoring comfort before the predicted return. Corvid Home, Inc. sells the Perch smart thermostat. Its paid "Away Assist" subscription performs all four steps on the homeowner's own thermostat and phone once the homeowner turns it on; an "alerts only" setting sends away notifications without touching the temperature. Every step happens on equipment the homeowner owns and operates, so homeowners are the direct infringers, and Corvid's exposure is inducement and contributory infringement. (Ambrose considered a second claim with a cloud-computing step and dropped it after charting it by actor: the claim also required the homeowner to select a comfort profile, Corvid did not condition the service on that selection, and Medgraph made the attribution theory a poor bet.)

What decided the case. Four choices mattered more than any brief. The March 2023 letter gave Ambrose a knowledge date no Delaware judge could question. The telemetry, plus one homeowner, made direct infringement uncontestable, which is where most indirect cases die. Corvid's opinion did real work: the jury evidently accepted that Corvid honestly and reasonably read the claim its way until the court said otherwise, which explains both the period split and the "no" on willfulness. And the opinion's protection expired with the construction ruling. A reading the court has rejected is hard to call a good-faith belief going forward, and Corvid kept the same help article and prompt for fifteen more months. A design change or revised instructions in September 2024 would likely have capped the damages at a few months of royalties.

What it cost. Each side spent roughly $2.5 million to $4 million to fight over a $3.4 million verdict. That arithmetic, not the doctrine, is why most indirect-infringement cases settle after claim construction or summary judgment, when both sides finally know which theory survives. Budget benchmarks by case size appear in the AIPLA Report of the Economic Survey, published every two years, and the full workflow is mapped in the Patent Litigation Toolkit: A Roadmap and Research Guide.

Decision points at a glance

Common mistakes

Patentees

• Relying on the complaint as the only source of knowledge in a court that rejects it, or mentioning a notice letter without attaching it or describing what it said.
• Pleading the whole product as the contributory "component" instead of the separable feature, and then describing the product's other uses in the complaint.
• Waiting for the expert to find a direct infringer. Subpoena a real user while discovery is open; E-Pass and Mirror Worlds are what happens otherwise.
• Letting contentions lag behind discovery and then losing the amendment for want of diligence (O2 Micro).
• Building one damages model with one start date, so that a jury finding on knowledge or good faith leaves no number to award.
• Proposing an inducement instruction that improves on the model language (Power Integrations).

Accused infringers

• Deciding the opinion-of-counsel question by default because the local-rule deadline passed.
• Producing telemetry before counsel has analyzed what it shows about noninfringing use.
• Sending witnesses into depositions willing to guess about what customers do (Cross Medical).
• Leaving the same instructions in place after losing claim construction, which turns a good-faith defense into a damages period, as the worked example shows.
• Skipping the Rule 50(a) motion on the direct-infringement predicate, or failing to renew it under Rule 50(b) (Unitherm).

Frequently asked questions

Do we have to name a specific customer who infringed? Not in the complaint: a class of direct infringers described with facts is enough under Bill of Lading. By summary judgment you need evidence that at least one person performed every step, which may be circumstantial (Toshiba, Lucent), but testimony from one real user is the safest proof.

Can the complaint itself supply the knowledge element? Courts are split. Many allow an indirect claim limited to conduct after the defendant received the complaint; others, following ZapFraud in Delaware, hold that knowledge supplied only by the complaint (or an earlier complaint in the same suit) cannot support an indirect claim in that suit. The assigned judge's own rulings matter most, and 2 Robert A. Matthews, Jr., Annotated Patent Digest § 10:44.50 collects the decisions. Plead pre-suit knowledge facts if you have them and post-suit knowledge in the alternative.

When does an accused infringer have to decide whether to rely on an opinion of counsel? By the deadline in the local patent rules or scheduling order, often 30 days after the claim construction ruling. Reliance waives privilege on the subject of the opinion; not relying carries no adverse inference under § 298.

Will a usage survey be excluded because it is imperfect? Rarely for imperfection alone. Vita-Mix and i4i treated methodological limits as matters of weight. Exclusion risk is highest when the survey asks the wrong people or measures uses of the wrong component.

If the court rejects our claim construction, does our opinion still protect us? For conduct before the ruling, a reasonable, honestly held reading can still negate intent and weigh against willfulness. After the ruling, continuing the same instructions makes good faith hard to claim, so revisit the instructions and the design promptly, as the worked example shows.

Can the patentee collect from both the vendor and its customers? Not twice for the same infringing units. Once full compensation is recovered from the direct infringer, a contributory infringer of the same infringement owes nothing more (Aro II), and settlement releases should say which units they cover.

How long does an indirect-infringement case take? Commonly two to three years from complaint to verdict, longer if the court stays the case pending inter partes review. The calendar is set by claim construction, which usually falls twelve to eighteen months after filing; see Filing or Defending an Inter Partes Review: A Practical Guide for how a parallel PTAB proceeding changes it.

Practical takeaways

• Indirect claims are won or lost on four facts: who directly infringed, when the defendant knew, what it told people to do, and whether the accused feature has real noninfringing uses. Organize every phase around them.
• Patentees: create a clean knowledge date before suit, find one real user early, and model damages for every date the jury might pick.
• Accused infringers: form and document a good-faith position early, make the opinion-of-counsel election deliberately, and revisit instructions after notice and again after claim construction.
• Frame the contributory component at the feature level, and prove substantiality with data rather than adjectives.
• Use model instructions, a special verdict that separates theories and periods, and timely Rule 50 motions; most reversals in this area come from the predicate, the instructions, or the damages base.
• For an element-by-element review of a claim or defense, work through the Indirect Patent Infringement Claim Checklist: A Practical Checklist.

This document is general information, not legal advice for any particular situation; the law changes, and the facts matter.

Related Documents

Related Articles

• Indirect and Divided Patent Infringement: Inducement, Contributory Liability, and the Akamai Problem: the doctrine behind every step in this guide, including the pharmaceutical and cross-border cases.
• What Constitutes Patent Infringement: Claims and Defenses: A Practical Guide: the direct-infringement rules that every indirect claim borrows.
• Expert Witnesses After the 2023 Amendment to Rule 702: Daubert, Disclosure, and Cross-Examination: the admissibility standard for technical, survey, and damages experts.
• Summary Judgment Under Rule 56: Winning and Surviving Before Trial: burdens and record-building for the motions in Phase 6.
• Attorney-Client Privilege and Work Product for Businesses: Upjohn, In-House Counsel, and the Common Interest: waiver and common-interest rules behind the opinion-of-counsel decision.

Related Guides

• Proving and Attacking Patent Damages: A Practical Guide: building the royalty case that starts at knowledge.
• Drafting an Answer and Affirmative Defenses: A Practical Guide: pleading the defenses listed in Step 7.
• Motions to Dismiss Under Rule 12: A Practical Guide for Plaintiffs and Defendants: the first test of the indirect counts.
• Taking and Defending an Expert Deposition: A Practical Guide: examining the experts who carry usage and damages proof.
• Designating and Playing Deposition Testimony at Trial: A Practical Guide: putting customer and corporate-designee testimony in front of the jury.
• Filing or Opposing Post-Trial Motions Under Rules 50, 59, and 60: A Practical Guide: the motions that test an inducement verdict.
• Finding, Qualifying, and Using Prior Art: A Practical Guide: the invalidity case that runs alongside the intent defense.
• Preparing and Defending a Rule 30(b)(6) Deposition: preparing the corporate witness on knowledge, instructions, and usage.
• Running an ANDA Litigation: A Practical Guide: where label-based inducement claims are litigated.

Related Checklists

• Indirect Patent Infringement Claim Checklist: A Practical Checklist: element-by-element review for either side.
• Litigation Hold and Evidence Preservation Checklist: A Practical Checklist: preserving instructions, telemetry, and the knowledge record.
• Expert Disclosure and Daubert Challenge Checklist: A Practical Checklist: deadlines and challenges for the reports in Phase 5.

Related Toolkits

• Indirect Infringement Toolkit: Knowledge Evidence, Direction or Control Proof, and Substantial Noninfringing Use Analyses: templates for the evidence this guide describes.
• Patent Litigation Toolkit: A Roadmap and Research Guide: the broader case workflow.
• Patent Damages Toolkit: Royalty Models, Expert Reports, and Daubert Motions: royalty-base and apportionment models.
• Jury Trial Toolkit: Voir Dire, Openings, Exhibits, and Instructions: charge and verdict-form templates.