The Complete Guide to Experimental Use in Patent Law: What Every Patent Practitioner and USPTO Patent Bar Candidate Must Know

The Complete Guide to Experimental Use in Patent Law: What Every Patent Bar Candidate Must Know

The experimental use doctrine represents one of the most nuanced and frequently tested areas on the USPTO Patent Bar examination. Understanding this doctrine isn’t just about memorizing rules—it’s about recognizing subtle fact patterns, applying multi-factor tests, and distinguishing between contexts where experimental use operates as a shield versus a sword. This comprehensive guide breaks down everything you need to know about experimental use for Patent Bar success and professional practice.

Understanding Experimental Use: Two Distinct Doctrines

You must understand that “experimental use” operates in two completely different contexts in patent law. Confusing these contexts is the number one mistake Patent Bar candidates make.

Context One: Experimental Use as Prior Art Negation (35 USC 102)

In this context, experimental use helps patent applicants by preventing their own pre-filing testing activities from being characterized as invalidating prior art. When an inventor tests their invention before filing a patent application, that testing could theoretically constitute “public use” that would destroy patentability. The experimental use doctrine says: if the use was genuinely experimental—not commercial—it doesn’t count as public use that creates prior art.

Context Two: Experimental Use as Infringement Defense (35 USC 271)

In this context, experimental use would theoretically protect someone who uses another person’s patented invention for experimental or research purposes. However, this defense has been narrowed dramatically by courts, particularly after Madey v. Duke University, and now provides almost no practical protection. Someone using a patented invention for research almost certainly infringes.

This doctrine appears less frequently on the Patent Bar but does show up occasionally, usually to test whether candidates understand its extremely limited scope.

Patent Bar Strategy: When you see “experimental use” in a question, immediately identify which context applies. Is the question about whether the inventor’s own activities create prior art (102 context), or whether someone else’s use of a patented invention constitutes infringement (271 context)? The analysis is completely different.

Experimental Use Under 35 USC 102

Let’s focus on the doctrine that matters most for the Patent Bar: experimental use as it relates to prior art and patentability.

Historical Foundation: The City of Elizabeth Case

The foundational case for experimental use doctrine is City of Elizabeth v. American Nicholson Pavement Co. (1877). In this case, the inventor laid an experimental pavement on a public street for six years before filing his patent application. Despite this lengthy public use, the Supreme Court held it was experimental use, not a public use that would bar patenting.

The Court identified several key factors:

• The inventor maintained control over the pavement and monitored its performance
• The purpose was testing durability and making improvements
• The inventor made modifications based on observed defects
• The use served his experimental purposes, not primarily public benefit

These factors still guide experimental use analysis today and appear repeatedly in Patent Bar questions.

Post-AIA Framework: The 102(a)(1) Grace Period and Experimental Use

The America Invents Act fundamentally restructured the prior art provisions of 35 USC 102, but experimental use doctrine remains relevant in modified form.

Key AIA Changes:

Under AIA 102(a)(1), prior art includes patents, printed publications, or activities that make the invention “in public use, on sale, or otherwise available to the public” before the effective filing date.

However, 102(b)(1) provides a critical grace period: disclosures made by the inventor (or those who obtained the subject matter from the inventor) within one year before filing are excluded from prior art.

How Experimental Use Fits:

The experimental use doctrine now operates primarily to determine whether an activity made the invention “available to the public” under 102(a)(1). If use was genuinely experimental—controlled, confidential, systematic—it arguably didn’t make the invention “available to the public” even if people other than the inventor were involved.

Example Scenario:

Inventor discloses invention at industry conference on March 1, 2024. This triggers the one-year grace period—inventor must file by March 1, 2025.

Competitor independently develops similar technology and begins controlled testing with third-party testers under NDA on July 1, 2024.

Inventor files application December 1, 2024.

Issue: Is the competitor’s testing 102(a)(1) prior art?

Analysis: If the competitor’s testing was genuinely experimental (controlled, confidential, data-driven), it may not have made the invention “available to the public” and thus wouldn’t constitute prior art. However, if testing lacked controls and confidentiality, it could be prior art that bars the inventor’s patent—even though the inventor disclosed first and filed within the grace period.

Patent Bar Testing: The exam loves scenarios where activities during the grace period potentially create prior art. You must analyze whether those activities truly made the invention “available to the public” or remained experimental and private.

Experimental Use in Different Technologies: Industry-Specific Considerations

The experimental use doctrine applies across all technologies, but its application varies significantly depending on the nature of the invention and testing requirements.

Pharmaceutical and Biotechnology Patents:

Drug development inherently requires extensive testing, including:

• In vitro studies
• Animal testing
• Phase I, II, and III clinical trials
• FDA regulatory submissions

Clinical trials involve hundreds or thousands of test subjects and extend over years. Yet these activities are consistently treated as experimental use, not public use creating prior art.

Why Clinical Trials Qualify as Experimental:

• Highly controlled protocols approved by institutional review boards
• Participants sign informed consent and confidentiality agreements
• Systematic data collection is the primary purpose
• Inventor (pharmaceutical company) maintains complete control
• Purpose is testing safety and efficacy, not commercial exploitation

Patent Bar Questions: The exam might present scenarios involving early-stage clinical trials and ask whether these activities create prior art. Apply the standard experimental use factors—control, confidentiality, systematic testing, purpose.

Software and Computer Technology:

Beta testing software presents unique experimental use challenges. Companies routinely release beta versions to thousands of users, ostensibly for testing. Does this constitute experimental use?

Factors Supporting Experimental Use:

• Beta testers agree to terms of service including confidentiality provisions
• Systematic bug reporting and feedback mechanisms exist
• Developer tracks usage data and implements fixes
• Product explicitly labeled “beta” or “test version”
• No payment required for beta access

Factors Against Experimental Use:

• Beta released to general public without screening
• No actual data collection or analysis infrastructure
• Primary purpose is building market awareness and hype
• Beta version functionally complete with only minor refinements expected
• Beta users essentially same as future customers

Critical Distinction: Beta testing to identify bugs = experimental use. Beta testing to generate publicity and gauge market interest = commercial activity, not experimental.

Mechanical and Electrical Inventions:

Physical products require real-world testing under actual use conditions. An inventor might test a new automotive component, construction material, or consumer electronics device.

Factors Examined:

• Where testing occurred (controlled facility vs. public venue)
• Who conducted testing (inventor’s employees vs. general public)
• Confidentiality of testing arrangement
• Documentation and monitoring of results
• Whether testing conditions matched intended use environment

Patent Bar Scenario: “Inventor provides prototype electronic devices to 20 individuals for ‘field testing’ over 14 months before filing. No written agreements signed. Inventor asks testers to ‘let me know how it works.’ Is this experimental use?”

Analysis: Likely NO. Without written confidentiality agreements, systematic data collection, or meaningful inventor control over the testing process, this appears commercial rather than experimental. The informal nature and lack of structure weighs against experimental characterization.

International Perspectives: Experimental Use in India and Global Practice

Understanding how experimental use operates in other jurisdictions enhances your competitive advantage as a patent practitioner and provides valuable context—even though the Patent Bar exclusively tests US law.

India’s Experimental Use Framework:

India’s Patents Act 1970 (as amended) addresses experimental use in Section 47(3), which provides that certain acts “for the purpose merely of experiment or research” do not constitute patent infringement.

Key Differences from US Law:

1. No Grace Period in India

Unlike the US’s 12-month grace period under AIA 102(b)(1), India provides no general grace period. Any public disclosure before filing can destroy patentability, subject to extremely limited exceptions for international exhibitions under Section 11(A).

Practical Implication: Indian inventors and companies must file patent applications BEFORE conducting any public testing. The experimental use doctrine doesn’t protect pre-filing activities in India the way it does in the US.

2. Narrower Experimental Use Exception to Infringement

Section 47(3) of India’s Patents Act provides that it’s not infringement to make, use, or sell the patented invention “for the purpose merely of experiment or research including the imparting of instructions to pupils.”

This language is narrower than even the already-narrow US experimental use exception. Indian courts interpret “merely” strictly, requiring that the experimental purpose be the sole or overwhelmingly primary purpose.

3. Bona Fide Research Emphasis

Indian patent jurisprudence emphasizes “bona fide” research purposes. Commercial research that happens to involve a patented invention—even if conducted by universities or research institutions—may still constitute infringement if it furthers the institution’s commercial or business objectives.

4. Reverse Engineering and Generic Drug Development

India’s patent system includes special provisions related to experimental use in the pharmaceutical context. Section 47(3) has been interpreted to potentially allow experimental work necessary for generic drug development before patent expiration (similar to the US Hatch-Waxman Act’s research exemption).

This reflects India’s policy emphasis on affordable medicines and balancing patent rights against public health concerns.

Comparative Analysis for Patent Practitioners:

When advising clients who file patents in both the US and India, consider these strategic implications:

Scenario: US-based client develops new pharmaceutical compound and wants to conduct clinical trials before filing patents.

US Strategy:

• Can conduct controlled clinical trials before filing
• Trials qualify as experimental use if properly controlled
• File within 12 months of any public disclosure
• Clinical trial data can be included in patent application

India Strategy:

• File provisional or complete patent specification FIRST
• Then conduct clinical trials (no public disclosure concern post-filing)
• Claim priority from US filing if coordinated properly
• Avoid any public disclosure before first filing anywhere

Cross-Border Best Practice:

1. File provisional application in US before any testing begins
2. Conduct experimental testing under controlled conditions
3. File complete specification within 12 months claiming provisional priority
4. File in India claiming priority to US provisional
5. Result: Protected in both jurisdictions with flexibility for testing

This approach maximizes protection while allowing necessary product development and testing.

Patent Bar Exam Strategies: How Experimental Use Questions Appear

Let’s break down exactly how the USPTO tests experimental use on the Patent Bar examination and how to maximize your score on these questions.

Question Type 1: Factor-Based Analysis

These questions present a detailed fact pattern involving pre-filing testing activities and ask whether the activity constitutes experimental use.

Example Structure:

“Inventor A develops a new construction material. On January 15, 2020, Inventor A provides samples to five construction companies for testing. The companies use the material in actual construction projects. Inventor A visits each site monthly and photographs the material. Inventor A keeps detailed records of performance observations. No confidentiality agreements were signed. Payment was not required for the material. Construction companies were told to report any problems directly to Inventor A. Testing continues through August 2021. Inventor A files patent application on November 1, 2021. Is the use from January 2020 through August 2021 experimental use that does not constitute prior art under 102(b)?”

How to Approach:

Create a mental or physical two-column chart:

Factors Favoring Experimental Use:

• Inventor maintained regular contact and oversight
• Systematic observation and documentation
• No payment exchanged
• Problems reported to inventor for analysis
• Materials tested in real-world conditions to evaluate performance

Factors Against Experimental Use:

• No confidentiality agreements (major negative factor)
• Testing in actual construction projects (suggests commercial use)
• Multiple unrelated companies involved (less control)
• Extended testing period without clear experimental protocol

Analysis: This is a close call, but the absence of confidentiality agreements and the commercial nature of the actual construction projects likely weigh against experimental use characterization. The inventor’s documentation efforts support experimentation, but without confidentiality controls, the use became sufficiently public to constitute prior art.

Best Answer: The use likely does NOT qualify as experimental use under the totality of circumstances, though reasonable arguments exist both ways.

Patent Bar Tip: In close-call scenarios, the exam usually provides answer choices that acknowledge the competing factors. Look for answers like “probably not experimental use because…” or “likely qualifies as experimental use despite…”

Question Type 2: Timeline Questions

These questions test whether you understand when the one-year clock starts ticking under pre-AIA 102(b).

Example Structure:

“Inventor begins testing prototype on June 1, 2011. Testing is conducted under controlled conditions with confidentiality agreements and systematic data collection through November 30, 2011. On December 1, 2011, Inventor begins selling the product commercially. Inventor files patent application on October 15, 2012. Is the application barred under 102(b)?”

Analysis:

• Testing from June through November 2011 = experimental use (doesn’t start the clock)
• Commercial sales begin December 1, 2011 = this starts the one-year clock
• Filing on October 15, 2012 = 10.5 months after commercial sales began
• Result: NOT barred—filed within one year of commercial activity

Critical Point: The experimental use period doesn’t count toward the one-year period. The clock starts when experimental use transitions to commercial activity.

Patent Bar Tip: Draw timelines. Mark when experimental use begins, when it transitions to commercial activity, and when filing occurs. Visual organization prevents mistakes.

Question Type 3: AIA vs. Pre-AIA Comparison

Some questions explicitly test whether you know the differences between pre-AIA and AIA treatment of experimental use.

Example Structure:

“Under pre-AIA 102(b), experimental use by the inventor could prevent the one-year on-sale bar from applying. How does the AIA modify this doctrine?”

Correct Answer: Under AIA 102(b)(1), inventor’s own disclosures (including offers for sale) within one year before filing are excluded from prior art. The experimental use analysis under AIA focuses on whether an activity made the invention “available to the public” under 102(a)(1).

Common Wrong Answers to Avoid:

• “AIA eliminates experimental use doctrine” (No—modifies its application)
• “AIA extends grace period to 18 months for experimental use” (No—remains 12 months)
• “AIA requires formal experimental use protocols” (No—same factual analysis applies)

Question Type 4: Experimental Use as Infringement Defense

Occasionally, the exam tests the extremely narrow experimental use exception to infringement.

Example Structure:

“University researcher uses patented laboratory equipment to conduct basic research on unrelated scientific questions. The research furthers the university’s legitimate research objectives and may lead to future grant funding. Does the experimental use exception protect the researcher from infringement liability?”

Correct Answer: NO. Under Madey v. Duke University, experimental use exception requires use “for amusement, to satisfy idle curiosity, or for strictly philosophical inquiry.” Research that furthers the university’s legitimate business objectives (even if non-commercial) does not qualify.

Patent Bar Tip: For infringement-side experimental use questions, remember the exception is essentially dead. Answer “does not qualify for exception” unless the facts are extremely compelling (which they won’t be on the exam).

Practical Application: Experimental Use in Patent Prosecution Practice

While the Patent Bar tests theoretical knowledge, understanding how experimental use operates in actual patent prosecution helps solidify concepts and prepares you for practice.

Scenario 1: Responding to 102 Rejections Based on Alleged Public Use

Your client’s patent application receives an Office Action rejecting claims under 102(a)(1) based on prior public use. The examiner cites evidence that the inventor demonstrated the invention at a trade show 14 months before filing.

Your Response Strategy:

1. Establish Experimental Purpose: Argue the demonstration was for experimental purposes—gathering feedback from industry experts about design improvements, observing user interactions to identify usability issues, etc.
2. Demonstrate Control: Show that demonstration attendees were required to sign visitor agreements, that the inventor maintained control over demonstration units, and that no units were distributed for unsupervised use.
3. Evidence of Testing: Submit declarations from the inventor detailing the experimental nature of the demonstration, including notes taken during the demonstration, subsequent modifications made based on feedback, and systematic evaluation of the testing results.
4. Distinguish from Commercial Activity: Emphasize that no sales occurred, no promotional materials distributed, and the demonstration was restricted to collecting technical feedback rather than marketing the product.
5. Apply Factors: Walk through the City of Elizabeth factors systematically, showing how each factor supports experimental use characterization.

Outcome: If you can demonstrate that the trade show demonstration maintained characteristics of controlled, systematic testing rather than commercial promotion, the examiner may withdraw the 102 rejection or you may overcome it through appeal.

Scenario 2: Advising Client on Pre-Filing Testing Strategy

Client develops breakthrough medical device and wants to test with physicians before filing patent application. How do you advise?

Recommended Testing Protocol:

1. File Provisional Application First: File provisional before ANY testing begins. This provides priority date and eliminates prior art concerns for testing that follows.
2. Written Testing Agreements: Draft comprehensive testing agreements with physician participants including:
   • Confidentiality obligations prohibiting disclosure
   • Return or destruction of test devices after testing period
   • Obligation to provide systematic feedback
   • Prohibition on commercial use of devices
   • Statement that testing is experimental in nature
3. Systematic Data Collection: Implement formal protocols for:
   • Performance metrics to be evaluated
   • Procedures for documenting results
   • Regular reporting requirements
   • Defect and issue tracking system
4. Inventor Control: Maintain strict control over test devices:
   • Serial number tracking
   • Scheduled inventor visits to test sites
   • Remote monitoring if technologically feasible
   • Limited distribution to select trusted testers
5. Documentation: Create comprehensive records including:
   • Testing protocols and objectives
   • Data collected from each test site
   • Modifications made based on testing
   • Analysis of testing results
   • Communications with testers

Result: Testing conducted under these conditions strongly qualifies as experimental use, providing maximum flexibility for product development while preserving patent rights.

Scenario 3: International Filing Coordination

US client wants to file patents in US, India, China, and Europe. Different experimental use doctrines apply in each jurisdiction.

Strategic Approach:

Phase 1 – Pre-Filing (Day 0):

• File US provisional application before any testing or disclosure
• Establishes priority date for all subsequent filings

Phase 2 – Testing Period (Months 1-10):

• Conduct controlled experimental testing under protocols described above
• All testing occurs AFTER US provisional filing, so no prior art concerns in any jurisdiction
• Collect data for inclusion in complete specification

Phase 3 – Complete Filing (Month 11-12):

• File US non-provisional claiming priority to provisional
• File PCT application claiming priority to US provisional
• Complete specification includes testing data and refinements

Phase 4 – National Phase (Months 30-32):

• Enter India, China, Europe, and other national phases claiming priority to original US provisional
• All jurisdictions recognize testing as post-filing activity
• No experimental use controversies in any jurisdiction

Benefit: This coordinated strategy works regardless of varying experimental use doctrines because testing occurs after the earliest priority filing, eliminating experimental use issues entirely.

Advanced Concepts: Edge Cases and Controversial Areas

Certain experimental use scenarios remain controversial or legally ambiguous. While these may not appear frequently on the Patent Bar, understanding them demonstrates sophisticated knowledge.

Edge Case 1: Third-Party Testing Without Inventor Knowledge

Suppose a third party independently obtains the inventor’s invention (perhaps by purchase or finding a discarded prototype) and conducts testing without the inventor’s knowledge or consent. Later, the inventor files a patent application.

Issue: Does the third party’s testing constitute prior art, and can experimental use doctrine apply?

Analysis: Experimental use doctrine traditionally requires inventor control and systematic testing for experimental purposes. Third-party testing without inventor knowledge lacks these elements. However, under AIA 102(a)(1), the question becomes whether the third party’s activities made the invention “available to the public.”

If the third party’s testing was conducted privately (even without the inventor’s involvement), it arguably didn’t make the invention available to the public and wouldn’t constitute prior art. However, if testing was public or results were disclosed, it could create prior art regardless of the third party’s intent.

Patent Bar Relevance: Questions testing this edge case would likely focus on whether activities made inventions “available to the public” rather than traditional experimental use factors.

Edge Case 2: Experimental Use After Commercial Sales Begin

Can an inventor continue experimental testing after commercial sales have already started?

Scenario: Inventor sells product commercially starting June 1, 2023 (starting the one-year clock). Inventor continues conducting experimental testing on improved versions through January 2024. Inventor files on May 15, 2024.

Analysis: The experimental testing after commercial sales began doesn’t stop the one-year clock that commercial sales triggered. The inventor must file within one year of the first commercial sale (June 1, 2024 deadline). The continued experimental work might support continuation or CIP applications claiming the improvements, but doesn’t extend the deadline for the original invention.

Critical Point: Once commercial activity begins, the clock is running. Experimental use can’t reset or extend it.

Edge Case 3: Confidential Sales for Testing Purposes

If an inventor sells units under confidentiality agreements explicitly for testing purposes, is this experimental use or an on-sale bar?

Traditional Analysis: Even confidential sales could trigger the on-sale bar under pre-AIA 102(b) if the invention was ready for patenting and a commercial offer for sale was made, regardless of whether the purpose was testing.

AIA Analysis: Under 102(a)(1), the question becomes whether the confidential sale made the invention “available to the public.” A sale under NDA to limited parties for testing purposes might not make the invention “available to the public” and thus wouldn’t constitute prior art.

Federal Circuit Guidance: The Federal Circuit has indicated that secret sales or offers can still constitute prior art under AIA 102(a)(1) in some circumstances, but the analysis remains developing.

Patent Bar Approach: If the exam presents confidential sales for testing, analyze both the experimental use factors AND whether the activity made the invention available to the public. The answer likely depends on the specific fact pattern.

Study Strategy: Mastering Experimental Use for the Patent Bar

Here’s how to efficiently master experimental use doctrine for maximum exam performance.

Week 1-2: Foundation Building

• Read MPEP 2133.03(e) (Public Use) thoroughly
• Study City of Elizabeth case and understand the factors
• Review pre-AIA vs. AIA framework differences
• Create flashcards for each experimental use factor

Week 3-4: Application Practice

• Complete 50+ practice questions specifically on experimental use
• For each question, write out the factors supporting and opposing experimental use
• Review explanations carefully, noting which factors exam writers emphasize
• Identify patterns in how questions are constructed

Week 5-6: Timeline Mastery

• Practice drawing timelines for complex scenarios
• Drill pre-AIA 102(b) on-sale and public use bar calculations
• Master the interaction between experimental use and grace periods
• Practice AIA 102(a)(1) and 102(b)(1) analysis

Week 7-8: Integration and Speed

• Complete full-length practice exams under timed conditions
• Focus on quickly identifying experimental use issues in fact patterns
• Practice eliminating wrong answers efficiently
• Review any missed experimental use questions and understand why

Key Memorization Priorities:

Must Memorize Cold:

• City of Elizabeth factors (all of them)
• Difference between 102 and 271 experimental use contexts
• Pre-AIA 102(b) framework
• AIA 102(a)(1) and 102(b)(1) framework
• Madey v. Duke holding on infringement-side experimental use

Should Know Well:

• Key cases: TP Laboratories, Electromotive, Invitrogen
• How experimental use interacts with on-sale bar
• Public use vs. experimental use distinction
• When confidentiality agreements matter

Less Critical (But Still Helpful):

• International experimental use doctrines
• Specific pharmaceutical testing protocols
• Software beta testing considerations

Final Exam Day Tips:

1. Read Fact Patterns Carefully: Experimental use questions are dense with facts. Every fact matters. Don’t skim.

2. Identify the Legal Framework First: Determine whether the question involves pre-AIA or AIA, 102 or 271, before analyzing facts.

3. Create Mental Checklists: As you read facts, mentally check off factors favoring and opposing experimental use.

4. Look for Controlling Factors: Absence of confidentiality agreements, lack of inventor control, or purely commercial purpose are often dispositive against experimental use.

5. Don’t Overthink: The exam tests doctrine, not policy. Apply the factors mechanically based on the facts given.

Conclusion: Experimental Use as Foundation for Patent Bar Success

Experimental use doctrine represents a microcosm of patent law complexity—requiring you to master statutory text, case law, multi-factor balancing tests, and practical application. Success on experimental use questions correlates strongly with overall Patent Bar performance because the skills required—careful fact analysis, application of legal tests, distinction between similar concepts—are fundamental to the entire examination.

By thoroughly understanding experimental use in both its 102 and 271 contexts, mastering the AIA frameworks, you’ll not only score well on these specific questions but also develop the analytical approach needed for success across all Patent Bar topics.

The experimental use doctrine isn’t just an exam topic—it’s a practical reality in patent prosecution. Mastering it for the Patent Bar prepares you for the real-world challenges of advising clients on pre-filing activities, responding to prior art rejections, and coordinating international filing strategies.

Ready to master experimental use and every other high-yield Patent Bar topic with structured, efficient preparation? Learn more about Wysebridge Patent Bar Review’s comprehensive, focused approach to exam success.