The Role of Technical Experts in Patent Litigation

Patent disputes turn on complex technology—neural network architectures, software algorithms, semiconductor designs, telecommunications protocols. Courts and juries cannot decide whether infringement occurred or whether patents are valid without understanding this technology at a deep technical level.12

That is where technical experts come in.

Technical expert witnesses analyse the technology at the heart of patent disputes and provide independent opinions that help courts understand technical issues. In high-stakes patent litigation, the quality and credibility of technical expert testimony can determine case outcomes, influence settlement values, and shape strategic decisions throughout the litigation lifecycle.34

In this article, we explain what technical experts do in patent litigation, when to engage them, what they deliver, and how they differ from other witnesses. We work as technical experts across software, AI, machine learning, and related technologies—analysing products, preparing claim charts, conducting prior art searches, and providing expert testimony at depositions and trials.

Important: This article provides general information about technical expert roles in patent litigation. It is not legal advice and should not be relied upon as such. Patent litigation involves complex legal considerations that require qualified legal counsel. Always consult a solicitor or patent attorney about expert engagement strategy for your particular case.

What Is a Technical Expert in Patent Litigation?

A technical expert is an independent specialist with deep domain expertise who analyses the technology at the heart of patent disputes and provides expert opinions to help courts understand technical issues.56 Unlike counsel who advocate for their clients, technical experts provide objective, independent analysis based on their specialised knowledge—a distinction that courts take seriously.78

Technical Experts vs Fact Witnesses

This distinction is fundamental to understanding expert evidence. Fact witnesses testify only about matters within their personal knowledge—events they observed, documents they created, or actions they took.9 They cannot provide opinions on technical or specialist matters because the rules of evidence restrict lay witnesses to testimony based on personal perception.10

Technical experts, by contrast, provide opinions on specialist matters within their expertise that ordinary witnesses cannot address. Under UK Civil Procedure Rules Part 35, experts can offer opinions on "matters calling for expertise" including technical, scientific, or other specialist practice issues.1112 In US federal litigation, Federal Rule of Evidence 702 permits experts to testify in the form of opinion if their specialised knowledge will help the trier of fact understand the evidence or determine a fact in issue.1314

The practical difference is significant: a software engineer who wrote the accused code can testify as a fact witness about what they did and why, but cannot offer opinions about whether that code infringes patent claims. A technical expert, having reviewed the code, can provide precisely that infringement opinion—along with the reasoning and analysis supporting it.1516

Technical Experts vs Damages Experts

Patent cases often involve multiple expert types serving distinct functions. Technical experts focus on liability questions—infringement and validity—addressing whether accused products practice claimed inventions, whether patents are valid over prior art, and technical aspects of claim construction.1718

Damages experts (typically economists, accountants, or licensing specialists) calculate financial damages, reasonable royalty rates, lost profits, and the value attributable to patented features.1920 Their analysis depends heavily on the technical expert's work: the scope of infringing features identified by the technical expert defines what the damages expert values.

In complex cases, you may also encounter industry experts who testify about market conditions and competitive dynamics, regulatory experts who address compliance issues, and survey experts who present consumer research data.21 The technical expert's role remains distinct: translating complex technology into understandable analysis that enables courts to resolve technical disputes.

When Technical Experts Are Engaged

Technical expert involvement spans from pre-litigation strategy through trial testimony, with different engagement patterns depending on case posture and strategy.2223

Pre-Litigation and Early Case Assessment

Before sending letters before action or filing lawsuits, patent holders engage technical experts to assess infringement.2425 Is there actually evidence that accused products practise the claimed invention? Element-by-element analysis at this stage can prevent pursuing weak cases that will not survive scrutiny—and can strengthen strong cases by identifying the most compelling infringement theories.26

For accused infringers, early technical expert engagement evaluates both non-infringement defences (does our product actually practise the claimed invention?) and invalidity arguments (can we find prior art that defeats the patent?).2728 This early assessment shapes litigation strategy, informs settlement discussions, and identifies the technical issues that will matter most at trial.

Strategic value of early engagement:

• Identifies weaknesses before committing to litigation positions
• Enables realistic case valuation for settlement discussions
• Allows time for thorough prior art searching
• Provides technical input for claim construction strategy
• Avoids costly mid-litigation expert changes

Claim Construction

Claim construction—the court's interpretation of patent claim terms—often determines case outcomes.29 In US practice, Markman hearings address claim construction as a matter of law, with the court interpreting disputed claim terms before infringement analysis proceeds.3031

Technical experts contribute to claim construction by explaining how terms would be understood by persons having ordinary skill in the relevant art (POSITA), a perspective central to proper claim interpretation.3233 While claim construction is ultimately a legal determination for the court, the technical expert provides the factual foundation about how skilled artisans would understand disputed terms in the context of the specification and prosecution history.34

Discovery

During discovery, technical experts review disclosed documents, analyse source code when available, test accused products, and examine technical specifications.35 For software patents, this may involve reviewing millions of lines of code under protective orders. For hardware, it may involve product teardowns, circuit analysis, and functional testing.36

The expert's role during discovery includes:

• Reviewing technical documents produced by both sides
• Identifying additional documents needed for complete analysis
• Analysing source code in confidential settings
• Testing products to understand actual functionality
• Consulting with counsel on technical aspects of discovery disputes

Expert Reports and Declarations

Technical experts prepare formal written reports or declarations that comply with applicable procedural requirements.3738 In US federal litigation, Federal Rule 26(a)(2)(B) requires testifying expert reports to include:

• Complete statement of all opinions and the basis and reasons for them
• Facts or data considered in forming opinions
• Exhibits supporting opinions
• Expert's qualifications, including publications from the past ten years
• List of cases in which the expert testified in the past four years
• Statement of compensation3940

These reports form the foundation for the expert's testimony and are exchanged with opposing parties according to court deadlines. The expert report is often the most important deliverable—a well-crafted report that clearly explains complex technical analysis can drive favourable settlement discussions or strengthen trial positions.41

Depositions

After expert reports are exchanged, opposing counsel takes expert depositions—questioning under oath about the expert's opinions, methodology, and analysis.42 Experts must defend their technical conclusions, explain their reasoning, and respond to challenges about their methodology and qualifications.43

Depositions are high-stakes proceedings. Empirical research shows that expert deposition performance directly influences settlement values, with weak or inconsistent testimony providing leverage for opposing parties.44 Every statement made at deposition can be used for impeachment at trial if testimony changes.45

Trial Testimony

At trial, technical experts testify before judges and juries, explaining the technology, presenting infringement or invalidity analysis, and withstanding cross-examination.46 The expert's role is educational—helping the fact-finder understand complex technical concepts well enough to decide whether infringement occurred or whether the patent is valid.47

Effective trial testimony requires translating technical analysis into accessible language without oversimplifying or losing accuracy. The best technical experts combine deep domain knowledge with communication skills that make complex technology understandable to non-technical audiences.48

Core Services Technical Experts Provide

Claim Chart Preparation

Claim charts are the foundation of infringement and invalidity analysis.4950 Technical experts prepare detailed element-by-element mappings showing how accused products do or do not practise patent claims, or how prior art teaches claimed inventions.

This requires:

• Deep understanding of the technology
• Ability to interpret patent claims correctly
• Product analysis through testing, reverse engineering, or source code review
• Clear presentation of technical evidence mapping claims to products or prior art[51]52

Infringement claim charts map each element of asserted patent claims to specific features of accused products, identifying the evidence (source code, technical documentation, test results) supporting each mapping.53

Invalidity claim charts map each claim element to teachings in prior art references, showing anticipation (single reference) or obviousness (combination of references with motivation to combine).54

We have discussed claim charts in detail in our article on what claim charts are and why they matter.

Prior Art Searching and Invalidity Analysis

Finding prior art that invalidates patents requires comprehensive searching across patent databases, academic publications, technical standards, and open source repositories.5556

For software and AI patents especially, we search where innovations in these fields are actually published: ArXiv preprints, GitHub repositories, major conference proceedings (NeurIPS, ICML, CVPR for machine learning; ACM and IEEE conferences for computer science), technical blog posts from research labs, and archived web content.5758

Once prior art is identified, technical experts evaluate whether it actually discloses the claimed invention (anticipation) or whether combining references would have been obvious, applying legal standards from cases like KSR International Co. v. Teleflex Inc.[59]60 The expert must consider the level of ordinary skill in the art, the scope and content of the prior art, and whether there was motivation to combine references.61

Source Code Review and Analysis

Software patent disputes often require analysing accused products' source code—the most direct evidence of what algorithms and methods are actually implemented.6263 Technical experts review code to determine:

• What algorithms are actually implemented
• How data structures are organised
• Whether claimed methods are practised
• How system architecture maps to patent claims
• Whether alternative non-infringing implementations exist64

This analysis occurs under protective orders maintaining code confidentiality, often in secured facilities designated by the producing party.65 We have conducted source code reviews ranging from focused modules (thousands of lines) to comprehensive system analysis (millions of lines).

Critical issue—source code authentication: Courts require proper authentication for source code to be admissible. In Wi-LAN Inc. v. Sharp Electronics Corp., the Federal Circuit affirmed exclusion of source code printouts as inadmissible hearsay, emphasising that "Rule 703 does not authorize admitting inadmissible evidence on the pretense that it is the basis for expert opinion."[66]67 Technical experts must work with counsel to ensure code evidence is properly authenticated through chain of custody documentation, contemporaneous creation records, and witness availability.68

Product Testing and Reverse Engineering

When source code is not available, technical experts test products and reverse engineer functionality.69 This might involve:

• Network traffic analysis to understand communication protocols
• API testing to determine system behaviour
• Binary reverse engineering for compiled software
• Hardware teardowns and circuit analysis
• System testing to document actual functionality vs marketing claims7071

Product testing provides objective evidence of how accused products actually work, independent of documentation that may be incomplete, outdated, or written for marketing rather than technical accuracy.72

Claim Construction Support

While claim construction is ultimately a legal determination, technical experts provide the technical perspective on how claim terms would be understood by persons having ordinary skill in the art.7374 This includes:

• Explaining technical concepts and their ordinary meanings
• Identifying industry standard terminology and definitions
• Analysing how particular implementations relate to claim language
• Reviewing intrinsic evidence (specification, prosecution history) from a technical perspective
• Providing context about the state of the art at the relevant time7576

Expert Declarations and Opinions

Technical experts provide formal opinions on:

• Infringement: Does the accused product practise the claimed invention?
• Non-infringement: Are claim elements missing or implemented differently?
• Invalidity: Does prior art anticipate or render obvious the patent claims?
• Validity: Can the patent withstand invalidity challenges?
• Claim construction: How should technical terms be interpreted?
• Design-around analysis: Are non-infringing alternatives available?7778

These opinions must meet applicable admissibility standards—in the US, Daubert standards requiring reliable methodology, sufficient facts and data, and proper application to case facts; in the UK, CPR Part 35 requirements for independence and assistance to the court.7980

What Makes an Effective Technical Expert

Domain Expertise

The expert must have genuine deep knowledge in the relevant technology area.81 Academic credentials, industry experience, publications, and patents in the field establish credibility and demonstrate the expertise needed to analyse complex technical issues.82

Under the Daubert standard (US) and similar frameworks internationally, courts assess whether the expert is qualified to apply reliable methodology to the issues at hand.83 Superficial knowledge or expertise in adjacent but different fields is not sufficient—courts and juries can identify experts who lack genuine understanding of the technology they are asked to analyse.84

Indicators of genuine expertise:

• Advanced degrees in relevant technical fields
• Industry experience developing or implementing relevant technologies
• Peer-reviewed publications in the technology area
• Patents demonstrating innovation in the field
• Recognition by professional organisations
• Track record of working with the technology, not just studying it85

Litigation Experience

Understanding patent litigation procedures, expert disclosure requirements, and how to work effectively with legal teams matters.86 Experts who have testified before understand deposition dynamics, court procedures, and how to explain complex technology to non-technical audiences.87

Courts have discretion to admit or exclude expert testimony, and experts with histories of Daubert challenges or disqualifications face heightened scrutiny.88 Litigation experience also means understanding:

• Disclosure obligations and timing requirements
• Privilege issues in attorney-expert communications
• How to maintain independence while supporting counsel's case theory
• What makes testimony persuasive to judges and juries89

Communication Skills

Technical experts must explain complex technology clearly to judges and juries without technical backgrounds.90 This requires:

• Translating technical concepts into accessible language
• Using visual aids, diagrams, and demonstrations effectively
• Responding to aggressive cross-examination calmly and clearly
• Teaching without condescending
• Acknowledging limitations and uncertainties honestly9192

The best technical analysis is worthless if it cannot be communicated persuasively. An expert who cannot explain their conclusions in terms a lay jury can understand will struggle to be effective, regardless of their technical credentials.93

Objectivity and Credibility

Under UK CPR Part 35, experts have an "overriding duty to help the court" that supersedes obligations to the party retaining them.9495 The expert's duty is to provide independent, objective opinions regardless of which side pays their fees.

While US federal rules do not explicitly require the same duty to the court, effective experts maintain objectivity.96 Experts who overstate conclusions, ignore case weaknesses, or act as advocates rather than independent analysts lose credibility.97 Courts and opposing counsel scrutinise expert opinions closely—credible analysis that acknowledges limitations is more persuasive than advocacy disguised as expertise.98

The credibility calculation: A single instance of overreaching or bias, once exposed, can destroy credibility for all of an expert's opinions. The safest approach is consistent objectivity, even when it requires acknowledging weaknesses in your retaining party's position.99

Consulting vs Testifying Experts

Federal Rule 26 and similar frameworks distinguish between consulting experts and testifying experts, creating important strategic options:100101

Consulting experts (also called non-testifying experts) are retained to assist with case strategy, evaluate technical issues, and support the legal team but are not disclosed to opposing parties and do not testify.102 Their work is generally protected from discovery under work product doctrine, allowing candid case assessment without fear that unfavourable analysis will be disclosed.103

Testifying experts are disclosed to opposing parties, must provide detailed reports, are subject to deposition, and may testify at trial.104 Everything they have reviewed, considered, or communicated regarding their opinions is potentially discoverable, with limited protections for attorney-expert communications under Rule 26(b)(4)(C).105

Strategic considerations:

1. Early consulting engagement: Retain a consulting expert early for case assessment without disclosure risk
2. Conversion option: If technical analysis supports your position, the consulting expert can become a testifying expert
3. Pivot capability: If analysis reveals case weaknesses, the work remains privileged and you can adjust strategy
4. Separate experts: In some cases, retain different consulting and testifying experts to preserve privilege on strategic analysis106107

Decision Framework: When to Engage a Technical Expert

Use this framework to determine whether and when technical expert engagement is appropriate:

Always Engage an Expert When:

• The technology is sufficiently complex that courts cannot understand it without expert assistance
• Infringement or validity turns on technical analysis (claim mapping, prior art evaluation)
• Source code review is required
• You need to establish the level of ordinary skill in the art
• Damages calculations depend on technical apportionment
• Opposing party has retained technical experts

Consider Consulting Expert First When:

• Case assessment is needed before committing to litigation positions
• You want candid analysis of both strengths and weaknesses
• Prior art searching may reveal uncomfortable results
• Settlement discussions would benefit from technical perspective
• You are uncertain whether expert testimony will be needed

Engage Testifying Expert When:

• Litigation is proceeding and expert disclosures are required
• Technical analysis supports your position
• You are prepared for full disclosure of expert's analysis
• Expert has appropriate credentials and communication skills
• Budget supports full expert engagement through trial

Timeline Guidance:

Stage	Action
Pre-litigation	Consulting expert for case assessment
Early litigation	Decide consulting vs testifying; begin substantive analysis
90+ days before trial (US)	Testifying expert report due per Rule 26(a)(2)
After report exchange	Expert depositions
Trial	Expert testimony

What NOT to Do: Critical Mistakes in Expert Engagement

These common errors can undermine technical expert effectiveness and damage cases. We have seen each of these mistakes cause significant problems:

1. Engaging Experts Too Late

The mistake: Waiting until expert disclosure deadlines force hurried engagement.

Why it fails: Complex technical analysis requires time. Rushed analysis produces weaker opinions, misses important issues, and creates vulnerability to Daubert challenges. Late engagement also eliminates the consulting expert option—once deadlines arrive, the expert must be disclosed.108

Better approach: Engage technical experts early, starting with consulting roles if case assessment is needed before commitment.

2. Selecting Experts Based on Credentials Alone

The mistake: Choosing the most credentialed expert without assessing communication skills, litigation experience, or fit with case theory.

Why it fails: Academic brilliance does not guarantee effective testimony. Experts who cannot explain their analysis clearly, who become combative under cross-examination, or whose approach does not fit the case theory can damage rather than help cases.109

Better approach: Evaluate communication skills, review prior testimony, conduct mock examination sessions, and ensure alignment between expert approach and case strategy.

3. Over-Claiming Expert Qualifications

The mistake: Presenting experts as having broader expertise than they actually possess, or allowing experts to opine on matters outside their genuine knowledge.

Why it fails: Opposing counsel will expose expertise gaps during deposition and trial. Once an expert is shown to have overstated qualifications in one area, credibility suffers across all opinions.110

Better approach: Be honest about expertise boundaries. If additional expertise is needed, engage supplementary experts rather than stretching existing experts beyond their knowledge.

4. Failing to Coordinate Multiple Experts

The mistake: Engaging technical experts, damages experts, and other specialists without ensuring their analyses are consistent and complementary.

Why it fails: Inconsistencies between expert opinions create impeachment opportunities. If technical and damages experts have different understandings of infringing features, opposing counsel will exploit the gap.111

Better approach: Coordinate expert engagement, ensure consistent fact bases, and review draft reports for alignment before finalisation.

5. Treating Experts as Advocates

The mistake: Expecting or encouraging experts to advocate for the retaining party rather than provide independent analysis.

Why it fails: Expert credibility depends on independence. Experts who appear to be advocates rather than independent analysts lose persuasive force with judges and juries. In UK proceedings, advocacy violates the expert's overriding duty to the court.112

Better approach: Select experts whose independent analysis genuinely supports your position; do not try to shape independent analysis into advocacy.

6. Inadequate Expert Preparation

The mistake: Assuming technical expertise translates automatically to effective testimony without preparation for depositions and trial.

Why it fails: Deposition and trial testimony require skills beyond technical analysis—understanding procedural rules, maintaining composure under aggressive questioning, and communicating complex concepts simply. Unprepared experts make avoidable mistakes that damage cases.113

Better approach: Invest in thorough preparation including mock depositions, review of prior testimony, and clear understanding of case strategy.

7. Ignoring Adverse Analysis

The mistake: Failing to address weaknesses identified in expert analysis or hoping opposing counsel will not discover problems.

Why it fails: Opposing experts and counsel will find weaknesses. Addressing problems proactively—through supplemental analysis, limiting opinion scope, or adjusting case strategy—is far better than having weaknesses exposed at deposition or trial.114

Better approach: Require experts to identify weaknesses in their analysis; address problems proactively rather than hoping they will not surface.

UK vs US: Expert Evidence Compared

Technical expert procedures differ significantly between UK and US patent litigation:

Aspect	United Kingdom	United States
Expert's Duty	Overriding duty to help the court (CPR Part 35.3)115	Duty to provide reliable, independent opinion (no explicit court duty)116
Court Permission	Required before expert evidence can be adduced (CPR Part 35.4)117	No permission required; parties control expert engagement118
Expert Reports	Single joint experts encouraged; sequential exchange of reports119	Each party retains own experts; simultaneous exchange typically120
Pre-Trial Testimony	Written reports exchanged; no pre-trial depositions121	Written reports plus expert depositions under Rule 30122
Cross-Examination	At trial only123	At deposition and trial124
Discussion Between Experts	Courts may direct experts to discuss issues and identify areas of agreement (CPR Part 35.12)125	No formal requirement; joint sessions occasionally ordered126
Single Joint Experts	Common in lower-value cases127	Rare; parties typically retain separate experts128
Cost Recovery	Expert costs recoverable subject to proportionality assessment129	Each party generally bears own expert costs unless fee-shifting applies130
IPEC Considerations	Costs caps limit recoverable expert fees (£60,000 liability + £30,000 quantum)131	No federal cost caps; ITC proceedings have different procedures132
Admissibility Standard	Reliability and assistance to court133	Daubert factors: testability, peer review, error rate, general acceptance134

Strategic Implications

For UK proceedings:

• Expert independence is paramount; courts actively police the expert's duty
• Fewer opportunities for pre-trial expert challenges; cross-examination occurs only at trial
• Joint expert discussions can narrow issues and reduce costs
• IPEC cost caps require careful budgeting of expert resources135

For US proceedings:

• Daubert challenges can exclude expert testimony pre-trial; prepare for admissibility fights
• Depositions allow extensive pre-trial testing of expert opinions
• Each party controls its own expert strategy without court permission requirements
• Expert costs can be substantial; budget for full engagement through trial136

Costs and Practical Realities

Understanding expert engagement costs helps with realistic budgeting and strategic decisions:

Expert Fee Ranges

Experience Level	US Hourly Rate	UK Equivalent
Junior Expert (5-10 years experience)	$300-500/hour	£250-400/hour
Mid-Level Expert (10-20 years experience)	$500-800/hour	£400-650/hour
Senior Expert (20+ years experience)	$800-1,500/hour	£650-1,200/hour
Renowned Industry Expert	$1,500-3,000+/hour	£1,200-2,500+/hour

Rates vary by technology area, geographic market, and specific expert credentials.137

Total Engagement Costs

For a complex patent case, typical technical expert costs include:

Activity	Estimated Hours	Cost Range (US)	Cost Range (UK)
Initial case assessment	10-30 hours	$5,000-30,000	£4,000-24,000
Claim chart preparation	40-100 hours	$20,000-100,000	£16,000-80,000
Prior art searching	20-60 hours	$10,000-60,000	£8,000-48,000
Source code review	40-120 hours	$20,000-120,000	£16,000-96,000
Expert report preparation	40-80 hours	$20,000-80,000	£16,000-64,000
Deposition preparation and attendance	20-40 hours	$10,000-40,000	£8,000-32,000
Trial preparation and testimony	30-60 hours	$15,000-60,000	£12,000-48,000
Total Range	200-490 hours	$100,000-490,000	£80,000-392,000

Cost Drivers

Factors that increase expert costs:

• Multiple patents-in-suit requiring separate analysis
• Large source code bases requiring extensive review
• Complex prior art landscapes requiring comprehensive searching
• Aggressive discovery schedules compressing timelines
• Multiple expert depositions
• Extended trial testimony

Factors that reduce expert costs:

• Clear, focused claim scope
• Available technical documentation reducing investigation needs
• Early settlement discussions informed by expert analysis
• Efficient coordination between legal team and expert
• IPEC cost caps limiting recoverable fees in UK proceedings138

Strategic Cost Considerations

Early consulting engagement: Investing in consulting expert assessment early (£10,000-30,000) can save substantial costs by identifying weak cases before full litigation commitment or by focusing resources on strongest arguments.

IPEC vs Patents Court (UK): IPEC cost caps (£60,000 liability, £30,000 quantum) limit recoverable expert fees regardless of actual expenditure. Cases in IPEC require disciplined expert budgeting; overspending will not be recovered even if you win.139

Settlement leverage: Strong expert analysis supporting your position can drive favourable settlements that avoid trial costs entirely. Expert investment that enables settlement at appropriate values provides excellent return.

Business Continuity Considerations

Technical expert engagement represents significant time commitment:

• Senior technical professionals may need to allocate 200+ hours over 12-24 months
• Deposition and trial attendance requires calendar flexibility
• Experts must maintain document retention and organisation throughout engagement
• Late-stage expert changes are extremely costly and disruptive

Key Takeaways for Engaging Technical Experts

Essential Principles

1. Early engagement provides maximum strategic value — Consulting expert assessment before litigation positions are fixed enables informed strategy decisions
2. Domain expertise is non-negotiable — Experts must have genuine deep knowledge in the relevant technology area, not adjacent or superficial familiarity
3. Communication skills matter as much as technical credentials — The best analysis is worthless if it cannot be explained clearly to non-technical audiences
4. Independence preserves credibility — Experts who advocate rather than analyse lose persuasive force
5. Preparation prevents problems — Invest in thorough preparation for depositions and trial; do not assume technical expertise translates automatically

Immediate Priorities When Engaging Experts

1. Define scope clearly — What technical questions need expert analysis?
2. Identify appropriate expertise — What domain knowledge is required?
3. Assess timing — Consulting expert for case assessment, or testifying expert for disclosure?
4. Evaluate candidates — Credentials, communication skills, litigation experience, availability
5. Establish coordination — How will expert work with legal team and other experts?

For Patent Holders:

• Engage technical experts before sending enforcement communications
• Use expert analysis to identify strongest infringement theories
• Prepare for invalidity challenges by understanding prior art landscape
• Budget for full expert engagement through trial; underfunding expert support undermines cases

For Accused Infringers:

• Engage experts early to assess both non-infringement and invalidity defences
• Prioritise comprehensive prior art searching—invalidity is often the strongest defence
• Understand source code authentication requirements before relying on code evidence
• Consider whether design-around analysis provides strategic options

Conclusion

Technical experts bridge the gap between complex technology and legal proceedings. They analyse accused products and prior art, prepare claim charts, provide expert opinions on infringement and validity, and testify at depositions and trials—translating specialised technical knowledge into analysis that courts can use to resolve disputes.

Effective technical experts combine domain expertise, litigation experience, communication skills, and objectivity. They understand both the technology deeply and how patent litigation works. They provide independent analysis that helps courts understand technical issues, maintaining credibility through honest acknowledgment of limitations and weaknesses alongside persuasive presentation of their conclusions.

We provide technical expert services across software, AI, machine learning, and related technologies. We have prepared claim charts, conducted prior art searches, reviewed source code, and testified in patent disputes. We understand what makes technical analysis credible and defensible—and we have seen the difference strong technical expertise makes in litigation outcomes.

If you are facing patent litigation—whether asserting claims or defending against them—technical expert engagement can determine the strength of your technical positions and your strategic options.

This is general information about technical expert roles, not legal advice for specific situations. Consult qualified patent counsel about expert engagement strategy for your particular case.

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Sources

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[30] Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). Federal Circuit guidance on claim construction methodology. Available at: https://caselaw.findlaw.com/us-federal-circuit/1156059.html

[31] Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc., 574 U.S. 318 (2015). Supreme Court decision on deference to factual findings underlying claim construction. Available at: https://supreme.justia.com/cases/federal/us/574/318/

[32] Manual of Patent Examining Procedure (MPEP) § 2141. Examination Guidelines for Determining Obviousness. Available at: https://www.uspto.gov/web/offices/pac/mpep/s2141.html

[33] Federal Circuit Bar Association. "Claim Construction Practice Guide." Available at: https://fedcirbar.org/

[34] Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576 (Fed. Cir. 1996). Intrinsic evidence priority in claim construction.

[35] Federal Rule of Civil Procedure 26(b)(1). Scope of discovery. Available at: https://www.law.cornell.edu/rules/frcp/rule_26

[36] Software Litigation Consulting. "Source Code Review for Patent Litigation." Available at: https://www.softwarelitigationconsulting.com/source-code-book/

[37] Federal Rule of Civil Procedure 26(a)(2)(B). Expert witness report requirements. Available at: https://www.law.cornell.edu/rules/frcp/rule_26

[38] UK Practice Direction 35. Expert Evidence supplementing CPR Part 35. Available at: https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part35/pd_part35

[39] Expert Institute. "Rule 26, Federal Rules of Civil Procedure: A Disclosure Guide for Expert Witnesses." Available at: https://www.expertinstitute.com/resources/insights/rule-26-federal-rules-of-civil-procedure/

[40] Federal Rule of Civil Procedure 26(a)(2)(B)(i)-(vi). Required contents of expert reports.

[41] TestifyingTraining. "How to Prepare Your Expert Witness for Deposition." SEAK. Available at: https://www.testifyingtraining.com/expert-witness-prepare-deposition/

[42] Federal Rule of Civil Procedure 30. Depositions by oral examination. Available at: https://www.law.cornell.edu/rules/frcp/rule_30

[43] SEAK. "The 10 Biggest Mistakes Expert Witnesses Make During Depositions." Available at: https://seak.com/the-10-biggest-mistakes-expert-witnesses-make-during-depositions/

[44] BlueNotary. "Using Deposition Testimony to Enhance Settlement Negotiations." Available at: https://bluenotary.us/leveraging-deposition-testimony-for-successful-settlement-negotiations/

[45] Federal Rule of Civil Procedure 32(a)(2). Using depositions at trial for impeachment.

[46] Federal Rule of Evidence 703. Bases of an expert's opinion testimony. Available at: https://www.law.cornell.edu/rules/fre/rule_703

[47] NITA. "Expert Testimony: A Guide for Expert Witnesses and the Lawyers Who Examine Them." National Institute for Trial Advocacy. Available at: https://www.nita.org/

[48] Expert Institute. "Establishing Credibility: Words and Phrases to Avoid as an Expert Witness." Available at: https://www.expertinstitute.com/resources/insights/establishing-credibility-words-and-phrases-to-avoid/

[49] Landslide Magazine (ABA). "Patent Claim Charts: A Primer." American Bar Association. Available at: https://www.americanbar.org/groups/intellectual_property_law/publications/landslide/

[50] Patent Litigation Support. "Preparing Effective Claim Charts for Patent Infringement Analysis." Available at: https://patentlitigation.expert/

[51] Barrgroup. "Source Code Review Services for IP Litigation." Available at: https://barrgroup.com/software-expert-witness/litigation-services/code-reviews

[52] IP Watchdog. "The Importance of Claim Charts in Patent Litigation." Available at: https://www.ipwatchdog.com/

[53] Manual of Patent Examining Procedure (MPEP) § 2143. Basic Requirements of a Prima Facie Case of Obviousness. Available at: https://www.uspto.gov/web/offices/pac/mpep/s2143.html

[54] 35 U.S.C. § 102. Conditions for patentability; novelty (anticipation). Available at: https://www.law.cornell.edu/uscode/text/35/102

[55] 35 U.S.C. § 103. Conditions for patentability; non-obvious subject matter. Available at: https://www.law.cornell.edu/uscode/text/35/103

[56] USPTO. "Prior Art Search Best Practices." Available at: https://www.uspto.gov/patents/search

[57] ArXiv.org. Preprint server for scientific papers. Available at: https://arxiv.org/

[58] IEEE Xplore Digital Library. Technical literature database. Available at: https://ieeexplore.ieee.org/

[59] KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007). Supreme Court decision on obviousness standard. Available at: https://supreme.justia.com/cases/federal/us/550/398/

[60] Graham v. John Deere Co., 383 U.S. 1 (1966). Framework for obviousness analysis. Available at: https://supreme.justia.com/cases/federal/us/383/1/

[61] Manual of Patent Examining Procedure (MPEP) § 2141.01. Scope and Content of the Prior Art. Available at: https://www.uspto.gov/web/offices/pac/mpep/s2141.html

[62] Lumenci. "Expert Source Code Review for Complex IP Litigation." Available at: https://lumenci.com/services/source-code-review/

[63] Software Litigation Consulting. "Source Code Analysis in Patent Cases." Available at: https://www.softwarelitigationconsulting.com/

[64] Oracle America, Inc. v. Google LLC, 886 F.3d 1179 (Fed. Cir. 2018). Source code analysis in software patent litigation.

[65] Model Protective Order for Litigation Involving Patents, Attorneys' Eyes Only provisions. Available at: https://www.aipla.org/

[66] Wi-LAN Inc. v. Sharp Electronics Corp., 992 F.3d 1366 (Fed. Cir. 2021). Source code authentication requirements. Available at: https://cafc.uscourts.gov/

[67] Knobbe Martens. "Hurdles in the Admissibility of Source Code and Expert Reliance on Unauthenticated Source Code." Available at: https://www.knobbe.com/blog/hurdles-admissibility-source-code/

[68] JD Supra. "Federal Circuit Affirms Refusal to Admit Source Code Printouts." Available at: https://www.jdsupra.com/legalnews/federal-circuit-affirms-refusal-to-3833197/

[69] Electronic Frontier Foundation. "Reverse Engineering FAQ." Available at: https://www.eff.org/

[70] IDA Pro. "Reverse Engineering Tools for Binary Analysis." Available at: https://hex-rays.com/ida-pro/

[71] Wireshark. Network protocol analyser. Available at: https://www.wireshark.org/

[72] IEEE. "Guidelines for Reverse Engineering in Intellectual Property Disputes." Available at: https://www.ieee.org/

[73] CPR Part 35.5. General requirement for expert evidence. Available at: https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part35

[74] Federal Judicial Center. "Reference Manual on Scientific Evidence." Third Edition. Available at: https://www.fjc.gov/content/reference-manual-scientific-evidence-third-edition-1

[75] Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898 (2014). Claim definiteness standard.

[76] O2 Micro International Ltd. v. Beyond Innovation Technology Co., 521 F.3d 1351 (Fed. Cir. 2008). Claim construction obligations.

[77] Stryker Corp. v. Zimmer, Inc., 837 F.3d 1268 (Fed. Cir. 2016). Damages expert analysis.

[78] Apple Inc. v. Samsung Electronics Co., 839 F.3d 1034 (Fed. Cir. 2016) (en banc). Design-around considerations.

[79] Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 593-94 (1993). Reliability factors for expert testimony.

[80] The Ikarian Reefer 1993 2 Lloyd's Rep 68. UK requirements for expert independence and duties to court.

[81] General Electric Co. v. Joiner, 522 U.S. 136 (1997). Expert qualification standards.

[82] Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999). Extension of Daubert to technical expert testimony.

[83] Federal Rule of Evidence 702(a). Expert qualification requirements.

[84] Expert Institute. "6 Expert Witness Mistakes to Avoid." Available at: https://www.expertinstitute.com/resources/insights/expert-witness-mistakes-avoid/

[85] National Academy of Sciences. "Standards for Expert Witness Qualifications." Available at: https://www.nationalacademies.org/

[86] SEAK. "How to Prepare Your Expert Witness for Deposition." Available at: https://blog.seakexperts.com/prepare-expert-witness-deposition/

[87] San Diego County Bar Association. "An Expert Witness' Perspective on Depositions." Available at: https://www.sdcba.org/

[88] In re Paoli Railroad Yard PCB Litigation, 35 F.3d 717 (3d Cir. 1994). Daubert application to expert qualifications.

[89] Federal Rule of Civil Procedure 26(b)(4)(C). Protection for attorney-expert communications.

[90] TestifyingTraining. "The Most Common Mistakes Expert Witnesses Make at Deposition." Available at: https://www.testifyingtraining.com/the-most-common-mistakes-expert-witnesses-make-at-deposition/

[91] NIJ. "Law 101: Legal Guide for the Forensic Expert—Exercising Caution." Available at: https://nij.ojp.gov/

[92] Advocate Magazine. "Preparing your retained-expert witness for deposition." Available at: https://www.advocatemagazine.com/

[93] ExpertPages. "How to Prepare an Expert Witness for a Deposition." Available at: https://www.expertpages.com/

[94] CPR Part 35.3(1). Expert's overriding duty to help the court.

[95] Kennedy v. Cordia (Services) LLP 2016 UKSC 6. Supreme Court guidance on expert evidence.

[96] Federal Rule of Evidence 702 Advisory Committee Notes (2000 Amendments).

[97] Claar v. Burlington N.R.R., 29 F.3d 499 (9th Cir. 1994). Expert credibility and objectivity.

[98] Quiet Technology DC-8, Inc. v. Hurel-Dubois UK Ltd., 326 F.3d 1333 (11th Cir. 2003). Expert advocacy versus analysis.

[99] Expert Institute. "Attorney beliefs concerning scientific evidence and expert witness credibility." Science Direct. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0160252715000473

[100] Federal Rule of Civil Procedure 26(b)(4)(D). Trial-preparation protection for consulting expert work.

[101] Westlaw Practical Law. "Depositions: Deposing an Expert Checklist." Available at: https://content.next.westlaw.com/

[102] Ager v. Jane C. Stormont Hospital, 622 F.2d 496 (10th Cir. 1980). Consulting expert privilege.

[103] In re Cendant Corp. Securities Litigation, 343 F.3d 658 (3d Cir. 2003). Work product protection for consulting experts.

[104] Federal Rule of Civil Procedure 26(a)(2)(A). Disclosure requirements for testifying experts.

[105] Federal Rule of Civil Procedure 26(b)(4)(C). Limited protection for attorney-expert communications.

[106] American Bar Association. "Protecting the Work Product of Consulting Experts." Available at: https://www.americanbar.org/

[107] Morrison & Foerster. "Expert Discovery Under the Federal Rules." Available at: https://www.mofo.com/

[108] Federal Rule of Civil Procedure 37(c)(1). Failure to disclose; sanctions.

[109] Courtroom Sciences. "5 Common Litigation Consulting Misconceptions." Available at: https://www.courtroomsciences.com/

[110] Brooke Group Ltd. v. Brown & Williamson Tobacco Corp., 509 U.S. 209 (1993). Expert qualification scrutiny.

[111] Micro Chemical, Inc. v. Lextron, Inc., 317 F.3d 1387 (Fed. Cir. 2003). Expert consistency requirements.

[112] National Justice Compania Naviera SA v. Prudential Assurance Co Ltd (The Ikarian Reefer) 1993 2 Lloyd's Rep 68. Expert duties in UK proceedings.

[113] Mock Deposition. "Expert Witness Preparation - Mock Deposition." Available at: https://www.mockdeposition.com/expert-witness-preparation/

[114] Weisgram v. Marley Co., 528 U.S. 440 (2000). Consequences of inadequate expert testimony.

[115] CPR Part 35.3. Experts—overriding duty to the court. Available at: https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part35

[116] Federal Rule of Evidence 702 (no explicit duty to court in US).

[117] CPR Part 35.4. Court's power to restrict expert evidence.

[118] Federal Rule of Civil Procedure 26(a)(2). Expert disclosure requirements without permission requirement.

[119] CPR Part 35.7. Single joint experts.

[120] Federal Rule of Civil Procedure 26(a)(2)(D). Timing of expert disclosures.

[121] UK Practice Direction 35. Expert reports in lieu of oral pre-trial testimony.

[122] Federal Rule of Civil Procedure 30(b)(6). Expert deposition procedures.

[123] CPR Part 35.11. Expert evidence at trial.

[124] Federal Rules of Civil Procedure 30 and 32. Deposition and trial use.

[125] CPR Part 35.12. Discussions between experts.

[126] Manual for Complex Litigation § 11.51. Joint expert sessions.

[127] Daniels v. Walker 2000 EWCA Civ 508. Single joint experts in UK practice.

[128] In re Welding Fume Products Liability Litigation, 245 F.R.D. 279 (N.D. Ohio 2007). US practice on separate experts.

[129] CPR Part 44.3. Proportionality in costs assessment.

[130] 35 U.S.C. § 285. Exceptional case fee shifting.

[131] UK Intellectual Property Enterprise Court Guide. Costs caps. Available at: https://www.gov.uk/government/publications/intellectual-property-enterprise-court-guide

[132] 19 U.S.C. § 1337. ITC investigation procedures.

[133] CPR Part 35.1. Expert evidence must be restricted to that reasonably required.

[134] Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). Reliability factors.

[135] Henderson v. Foxworth 2014 UKSC 41. Appellate review of expert evidence.

[136] AIPLA. "2023 Report of the Economic Survey." Expert witness costs data. Available at: https://www.aipla.org/

[137] Expert Witness Institute. "Expert Witness Fee Survey." Available at: https://www.ewi.org.uk/

[138] Stobbs IP. "Costs Management in UK Patent Litigation." Available at: https://www.stobbs.co.uk/

[139] IPEC Guide. Small Claims Track and Multi-Track procedures. Available at: https://www.gov.uk/government/publications/intellectual-property-enterprise-court-guide