37.3% 20.6% 11.4%30.8%
Notes and Sources: See Table 3. Panel A presents the distribution of all of the patents the patentees obtained over their careers and Panel B presents the distribution for one patent per patentee, where the patent is selected randomly from the patentee’s record. Only assignments at issue are included in the figures.
Contractual Mobility of “Great Inventors”
number of different assignees over career
Birth Cohort no assignees 1 assignee 2 assignees 3 assignees 4 assignees 5 or more assignees n
patents 2.3 34.1 5.4 11.3 5.5 41.4 815
inventors 11.5 27.1 26.0 9.4 12.5 13.5 96
patents 7.3 21.1 20.2 8.2 12.7 30.5 2480
Notes and Sources: The sample of “great inventors” encompasses all of the 249 individuals recognized as important inventors in the Dictionary of American Biography who were born after 1819 and before 1886 and who were active in the U.S. For each person (248 men and 1 woman), we collected biographical information as well as roughly a 20 percent sample of the patents he/she were ever awarded (all patents received before 1847, and then one out of every five years from 1850 through 1930). Here we report the distributions computed over the 96 great inventors for whom we have sampled ten or more patents. Because we have only sampled one fifth of the patents on average and are confining our analysis to assignments at issue, we are underestimating the full extent of contractual mobility.
Regional Patterns of Migration by the Great Inventors