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→Lerner et al 2011
Final sample consists of 6398 patents from 472 firms granted from 1984 through may 2007.
Robustness Checks:
*Concern one: Private equity investments for which there was already an existing investor, patents may be double-counted. Employs these patents only the first time they appear then drops them. Results are little changed
*Concern two: Only measures citation count during the 3 years after the award. Using a longer window increases accuracy but decreases sample size. Repeats the analysis through the end of the second calendar year after the patent grant and after the fourth year and finds that results are quantitatively similar.
*Concert three: In divisional buyouts corporate parents may retain best patents and only give low quality patents to the PE backed division. This may lead to an apparent increase in quality in the patents applied for after the award. Addresses this issue by using the longer window for patents above and by rerunning cross tabulations and regressions with divisional buyouts excluded from the sample. Key results are little changed by this shift.
Variables:
