classification-navigation

Research

IPC/CPC hierarchy drill-down and lateral expansion for patent discovery

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Classification Navigation

Navigates the IPC/CPC patent classification hierarchy to discover patents through structured taxonomy traversal — drilling down into subclasses and expanding laterally to related classes.

Stages

1. Top-Level Classification Identification

Determine relevant IPC/CPC sections and classes from seed patents or technology description
Map the technology domain to classification entry points
Identify primary and secondary classification codes

2. Subclass Drill-Down

For each identified class, drill into subclass, main group, and subgroup levels
Assess patent density at each level
Identify the most specific relevant classification codes

3. Lateral Expansion to Related Classes

From identified subclasses, explore sibling and cousin classes
Follow "see also" and "related" cross-references in classification schemes
Identify adjacent technology areas that may contain relevant patents

4. Cross-Reference Validation

Verify that lateral expansion yields relevant results
Check that discovered classes actually contain patents related to the target technology
Prune irrelevant branches and confirm final classification scope

Available SOPs

SOP	Role
patent-query-formulation	Generate IPC/CPC-based search queries
patent-categorization	Validate classification relevance of found patents
saturation-detection	Determine when classification space is fully explored

Execution Guidance

Start broad (section/class level) and narrow down based on relevance
IPC and CPC diverge at subgroup level — check both schemes
Pay attention to classification reform dates — codes may have changed
Cross-references in CPC scheme definitions reveal non-obvious connections
A single invention often spans 3-5 classification codes — always check secondary classifications

Yield Report

Report to calling strategy after each execution:

Classification codes explored (with depth level)
New relevant codes discovered
Patent count per classification code
Coverage assessment (% of relevant classification space explored)

Available SOPs

Optional, no fixed order; the final leaf is always a sop.

SOP	When to use
knowledge-acquisition-saturation-detection	Determine when additional searching yields diminishing returns. Analyzes the latest expansion batch against existing corpus to judge continue/near-saturation/saturated. Used by snowball and systematic-survey.
patent-categorization	Classify patents by tech subdomain, application scenario, and value chain position
patent-query-formulation	Construct keyword + IPC/CPC + assignee combination search strategies for patent databases