classification-navigation

name	classification-navigation
description	IPC/CPC hierarchy drill-down and lateral expansion for patent discovery
execution	tactic
dependencies	{"sops":["knowledge-acquisition-saturation-detection","patent-categorization","patent-query-formulation"]}

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