Time in purgatory: Examining the grant lag for U.S. patent applications

David Popp, Ted Juhl, Daniel K.N. Johnson

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


As patent applications increase, and the range of patentable technologies increases, the length of time it takes for an invention to go through the examination process at the U.S. Patent Office has increased. Concerns over the distributional effects of these changes have been expressed during policy debates. We use data on U.S. patent applications and grants to ask who is affected by longer grant lags. We augment this analysis with interviews of patent examiners, leading to a better understanding of the examination process. Our analysis finds that differences across technology are most important. These differences do not erode over time, suggesting that learning effects alone will not reduce grant lags. Inventor characteristics have statistically significant effects, but the magnitudes are small.

Original languageEnglish (US)
Pages (from-to)783-827
Number of pages45
JournalTopics in Economic Analysis and Policy
Issue number1
StatePublished - 2004


  • Examinations
  • Grant lags
  • Patents

ASJC Scopus subject areas

  • General Economics, Econometrics and Finance


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