CPC Subclass Reclassification: Patent Family Churn Data 1985-2019

Cooperative Patent Classification (CPC) subclass reclassifications are tracked across three periods (2013-2023) for patent families filed between 1985 and 2019. Created by P. Persoon, the data quantifies the volume of added and deleted classifications for DOCDB patent families containing at least one US member.

Use Cases

• Analyzing subclass stability by comparing the ratio of added classifications (rp) to deleted classifications (rn)
• Modeling the growth or decline of technology sectors using the subclass count before reclassification (n)
• Investigating historical classification shifts for patent families filed between 1985 and 2019

Strengths

• Covers three distinct reclassification windows: 2013/2016, 2016/2019, and 2019/2023
• Includes longitudinal data for filing years 1985 through 2019
• Provides granular counts of added (rp) and deleted (rn) classifications per subclass

Limitations

• Excludes patent families with a size of 1 or those lacking a US member
• Aggregated at the subclass level, preventing analysis of individual patent documents
• Filing year data ends at 2019, potentially missing recent innovation trends

Provenance

Source

P. Persoon, DANS Data Station Social Sciences and Humanities Collection

Collection Method

Aggregated from DOCDB patent family records

Time Range

1985-2019

Freshness

Last updated March 2026; covers filing years up to 2019.

Geography

United States