How to count patents

Post date: Jul 28, 2010 2:41:22 PM

Previously, counting patents was a bit tricky because patents could have multiple assignees and these were stored in file PATASSG but not in the utility patent file.

Now, file PAT76_06_ASSG includes records for all assignments of each patent. For example, there are two records for patent 5187368, one for Glaxo (PDPASS == 11119583) and one for the University of Kentucky (PDPASS == 10367449).

To count patents one might use different rules, depending on the purpose. If one assumes that patent rents are split evenly between multiple assignees, for instance, then Glaxo would get only half the rents for this patent. We might want to count Glaxo's ownership as 1/2.

Here is a snippet of Stata code you might want to use to count in this way:

use pat76_06_assg,clear

* count number of assignees for each patent

by patent: egen nass = count(pdpass)

tab nass

* calculate fractional patent ownership

gen npat = 1 / nass

These values can then be accumulated by year, firm, etc.