How to create a claims and defenses evidence matrix for Patent Infringement Matters

Create a patent claims and defenses evidence matrix by separating each asserted theory, patent claim, accused product version, and defense into traceable rows. Record the proposition being tested, supporting and contrary evidence, legal dependencies, unresolved facts, and the responsible reviewer. Connect limitation-level analysis to exact claim-chart cells and source references rather than compressing it into conclusions. The deliverable is an internal decision document showing what the reviewed record supports, where interpretation or missing evidence limits the assessment, and which targeted evidence task comes next.

When to use this workflow

Use this workflow when litigation counsel or an in-house team must assess infringement contentions, evaluate a technical production, compare expert positions, or identify evidentiary gaps before depositions or motion preparation. It is especially useful when multiple patents, dependent claims, product releases, or invalidity theories make a narrative assessment difficult to audit.

This guide addresses US federal district-court litigation. Check applicable rule versions, local patent rules, the assigned judge’s orders, and protective-order restrictions. Federal procedure does not automatically govern state proceedings, arbitration, ITC investigations, or PTAB proceedings.

The matrix does not replace required contentions, limitation charts, or substantive legal research. For example, Northern District of California Patent L.R. 3-1 requires specified infringement disclosures and charts locating each limitation. Those rules cover the utility-patent actions described in Rule 1-2, and the court may modify obligations under Rule 1-3. Patent Local Rules, Rules 1-2, 1-3, and 3-1. (cand.uscourts.gov)

What you need

Assemble a controlled working set before assigning conclusions:

• Patent materials: issued claims and dependencies, specifications, prosecution records, asserted-claim lists, and claim-construction orders or disputed constructions.
• Positions and scope: pleadings, current infringement and invalidity contentions, responses, asserted defenses, accused instrumentalities, and relevant versions and periods.
• Technical evidence: source-code snapshots, build identifiers, schematics, configuration records, testing materials, manuals, and engineering testimony.
• Other issue evidence: identified prior-art references and date evidence; ownership, licensing, notice, marking, and sales records relevant to identified issues.
• Source controls: production indexes, Bates ranges, native-file identifiers, confidentiality designations, protective-order restrictions, and existing claim charts.

Keep witness testimony, attorney interviews, expert interpretation, and counsel’s inference distinguishable. Identify unavailable repositories and restricted materials at intake so an incomplete collection is not mistaken for negative evidence.

Use the template

The companion template is Patent Infringement Matters — Claims and defenses matrix. Copy this table into your working document or spreadsheet. Split rows when the theory, claim, materially relevant version, configuration, or defense changes.

ID / scope identifies the patent, claim, accused version, relevant period, and theory or defense. Give each row a stable identifier, such as M-014, with child identifiers for limitation-specific questions. Identify the served contention or other document defining that scope.

Proposition states a testable assertion, not “infringement established.” Legal / burden check records the applicable authority, construction dependency, and issue-specific burden question. Distinguish the burden of proof from the practical task of obtaining evidence; do not assume every defense presents the same burden.

Support and Contrary evidence contain document IDs, pinpoint citations, and explanations of relevance. Gaps / foundation identifies missing facts, provenance, witness knowledge, and admissibility questions. Assessment distinguishes documented facts from inference. Action / owner names a concrete task and accountable reviewer, with an internal target date where useful.

Step by step

1. Fix the scope and units of analysis

Start with a dated list of asserted patents, claims, theories, defenses, and accused versions. Reconcile it against current positions rather than an earlier complaint or superseded chart. Record the document defining scope.

Separate literal infringement and equivalents positions where asserted. Identify indirect-infringement issues separately: evidence of product operation should not silently stand in for evidence addressing other elements of the asserted theory. Add ownership, licensing, notice, or damages rows only when relevant to this assessment.

For validity issues, identify which claims are challenged; add product-version information only if it matters to that issue.

Record: stable row IDs, scoped propositions, and controlling position documents. Mark scope disputes rather than adopting one side’s characterization silently.

2. Map propositions to claim language and legal questions

Preserve issued claim wording and dependencies in the linked chart. Identify the limitation and construction on which each proposition depends. If construction remains disputed, record the alternative assumptions and explain whether the factual assessment changes under each.

Specify the actual defense contention. An invalidity row should identify the reference or combination and proposed mapping, not merely say “prior art.” Northern District of California Patent L.R. 3-3 requires prior-art identification, anticipation or obviousness positions, identified combinations, and limitation charts. These are disclosure requirements, not findings of invalidity. Patent Local Rules, Rule 3-3. (cand.uscourts.gov)

Record: chart-cell references, construction assumptions, and assigned legal and burden-verification questions. Keep unverified propositions provisional.

3. Attach evidence at the correct technical granularity

For each supporting item, record its exact location and what it establishes. A manual describing a feature does not necessarily establish operation in every accused build. A code citation should identify the snapshot, path or function, and relevant lines, subject to access restrictions.

Distinguish observed test behavior from an engineer’s explanation and an expert’s interpretation. Preserve test conditions and configurations. For prior art, separate publication, public-accessibility, filing, and other potentially relevant dates; assign eligibility analysis rather than inferring it from a document’s appearance.

Record: pinpoint support, source type, and evidentiary limits. If only a related version was inspected, state that limitation rather than extending the finding across the product family.

4. Search deliberately for contrary evidence

Assign a reviewer to test each proposition against the record. Look for disabled features, alternative code paths, configuration changes, inconsistent testimony, missing limitations, conflicting dates, and exceptions in licensing or sales records.

Distinguish “no contrary evidence identified in the reviewed set” from “no contrary evidence exists.” An empty search result does not establish that an event never occurred. Record the reviewed materials and collection boundaries affecting any inference.

Record: contrary sources and whether they defeat, narrow, or question the proposition. Retain contradictions even when counsel considers them explainable, and cite the evidence supporting that explanation.

5. Test provenance, foundation, and handling restrictions

Identify who can explain each important source and whether its origin, completeness, and version are established. Evidence Rule 901 requires sufficient evidence supporting a finding that an item is what its proponent claims; testimony from a knowledgeable witness is one identified method. Authentication alone does not resolve hearsay, relevance, or other admissibility questions. Federal Rules of Evidence, Rule 901. (uscourts.gov)

Check protective-order and source-code restrictions before reproducing excerpts. Control access to sensitive legal analysis rather than assuming a confidentiality or work-product label settles protection.

Record: the prospective foundation witness or other authentication route, unresolved evidentiary questions, and handling restrictions. Reference controlled sources instead of copying restricted contents into a broadly circulated matrix.

6. Convert gaps into proportionate evidence tasks

Replace “need more discovery” with a task tied to a missing proposition: inspect a deployed configuration, locate a build manifest, obtain publication evidence, or test a witness’s basis of knowledge.

Rule 26(b)(1) limits federal discovery to nonprivileged matter relevant to claims or defenses and proportional to the case; discoverability does not require admissibility. Relevance alone therefore does not establish that a proposed request is appropriate. Federal Rules of Civil Procedure, Rule 26(b)(1). (uscourts.gov)

Record: the evidence sought, decision it would inform, likely source, owner, and priority. Separate internal target dates from court-imposed deadlines. Prefer the smallest useful task before broader discovery.

7. Review assessments and preserve changes

Have the responsible lawyer review the proposition, citations, contrary evidence, and legal dependencies together. Use assessments such as “supported for inspected build,” “contradicted by current record,” or “unresolved pending configuration evidence.” Avoid confidence scores that hide uncertainty.

Record the matrix version, review date, and material changes. Preserve enough prior reasoning to explain changed assessments. Refer potential changes to served contentions for separate procedural review; an internal status change is not itself an amendment.

Record: the reviewed assessment, outstanding assignments, and next review trigger, such as a specified production or technical test.

Worked example

Fictional scenario: Alder Signal Labs alleges that Birch Harbor Devices’ RelayBox infringes claim 6 of fictional Patent P-17. For this example, the disputed limitation concerns selecting a transmission interval using a stored congestion threshold. Counsel evaluates versions 2.0 and 2.1 and a proposed invalidity position involving a fictional Mariner reference.

The working set contains selected code, two guides, a test report, and a scanned reference. Deployment configurations and independent publication evidence are unavailable. The table addresses only the disputed limitation; other limitations remain in the linked chart and are not resolved here. All parties, documents, technical language, and citations are fictional.

The matrix changes the immediate decision. Reading a threshold does not establish that it determines interval selection, and fixed intervals do not establish that threshold logic was bypassed. Code-path analysis and configuration evidence take priority over a product-wide conclusion. Mariner remains a candidate because neither its technical teaching nor its eligibility is resolved. Counsel can assign focused tasks without manufacturing missing evidence.

Common mistakes

• One row for an entire product family. Split materially different versions and configurations; cite evidence connecting any versions assessed together.
• Replacing limitation analysis with an infringement label. Link propositions to exact claim language, dependencies, and chart cells.
• Combining references into an unexplained invalidity conclusion. Identify each theory and combination separately, including unresolved eligibility and mapping questions.
• Treating interview notes as equivalent to testimony. Label source types and assign verification through the witness or underlying record.
• Turning the matrix directly into a court exhibit. Conduct a separate presentation and admissibility review. Rule 1006 addresses summaries of voluminous admissible materials that cannot conveniently be examined in court and requires availability of underlying originals or duplicates. Illustrative aids are addressed separately by Rule 107. Federal Rules of Evidence, Rules 1006 and 107. (uscourts.gov)

Final quality check

• Each row identifies its claim, theory or defense, relevant version, and scope source.
• Claim wording, dependencies, and construction assumptions match the linked chart.
• Material factual assertions have verified pinpoint citations and accurate source labels.
• Contrary evidence and collection limits appear beside the assessment.
• Prior-art dates, eligibility questions, theories, and mappings remain distinct.
• Legal propositions and burdens are verified or assigned for verification.
• Foundation issues and open gaps have owners and specific next actions.
• The reviewed version is labeled for internal analysis and reconciled with current positions.

Complete the workflow with DecoverAI

DecoverAI is the Legal Intelligence Platform for litigation and transactions. Its document review, evidence analysis, privilege and confidentiality analysis, and deposition preparation capabilities can support review of the source record and follow-up factual questions. Lawyers retain responsibility for citations, technical interpretations, and legal conclusions. The matrix is counsel’s working document, not a claimed dedicated product module. To discuss this evidence-analysis workflow, book a demo.

Frequently asked questions

Is this matrix the same as a patent claim chart?

No. A claim chart maps limitations to cited material. The matrix connects those mappings to contrary evidence, defense theories, legal dependencies, and assigned actions. Link the documents rather than maintaining inconsistent duplicate mappings.

How should dependent claims be handled?

Identify dependencies and link inherited limitations to their existing analysis. Give additional limitations traceable entries. Do not treat evidence of the additional feature as resolving the entire dependent claim.

Should privileged interviews appear in the matrix?

Counsel should decide what belongs in each controlled document. Label interview-derived assertions, limit unnecessary sensitive detail, and review access. Do not assume that combining records with counsel’s comments establishes protection for everything included.

When should the team update a row?

Update it when new evidence, construction assumptions, revised contentions, or verified authority affects the assessment. Record what changed and why, and revisit related rows relying on the same source or assumption.

Sources

• Federal Rules of Civil Procedure: Rule 26(b)(1), federal discovery scope and proportionality.
• Northern District of California Patent Local Rules: Rules 1-2, 1-3, 3-1, and 3-3, district-specific scope and contention requirements.
• Federal Rules of Evidence: Rules 901, 1006, and 107, authentication, evidentiary summaries, and illustrative aids.

This guide is general information about legal workflows, not legal advice for any matter. It was drafted and reviewed with AI assistance. The worked example is fictional. Contract rights and procedure depend on the governing law, the actual wording, and the facts, so check the cited sources and the rules that apply in your jurisdiction before relying on it.