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A Survival Analysis of the Approval of U.S. Patent Applications



We model the length of time that it takes for a patent application to be granted by the U.S. Patent and Trademark Office, conditional on the patent actually being awarded eventually. Survival analysis is applied and both the nonparametric Kaplan-Meier and parametric accelerated failure time models are used to analyze the data. We find that the number of claims a patent makes, the number of citations a patent makes, the patent’s technological category, and the type of applicant all have significant effects on the duration that a patent is under consideration. A log-normal survival model is the preferred parametric specification, and the results suggest that the hazard function is non-monotonic over time.

Suggested Citation

  • Ying Xie & David E. Giles, 2007. "A Survival Analysis of the Approval of U.S. Patent Applications," Econometrics Working Papers 0707, Department of Economics, University of Victoria.
  • Handle: RePEc:vic:vicewp:0707 Note: ISSN 1485-6441

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    References listed on IDEAS

    1. Kennan, John, 1985. "The duration of contract strikes in U.S. manufacturing," Journal of Econometrics, Elsevier, vol. 28(1), pages 5-28, April.
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    Cited by:

    1. repec:spr:scient:v:111:y:2017:i:3:d:10.1007_s11192-017-2354-6 is not listed on IDEAS
    2. Aka, Joël, 2017. "Market approval of phytosanitary active substances in Europe: An empirical duration analysis," Food Policy, Elsevier, vol. 68(C), pages 143-153.
    3. Andrew Eckert & Corinne Langinier, 2014. "A Survey Of The Economics Of Patent Systems And Procedures," Journal of Economic Surveys, Wiley Blackwell, vol. 28(5), pages 996-1015, December.
    4. repec:spr:scient:v:111:y:2017:i:2:d:10.1007_s11192-017-2324-z is not listed on IDEAS
    5. repec:spr:scient:v:111:y:2017:i:3:d:10.1007_s11192-017-2357-3 is not listed on IDEAS
    6. Gupeng, Zhang & Xiangdong, Chen, 2012. "The value of invention patents in China: Country origin and technology field differences," China Economic Review, Elsevier, vol. 23(2), pages 357-370.

    More about this item


    Patents; research and development; survival analysis; hazard function;

    JEL classification:

    • C16 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods and Methodology: General - - - Econometric and Statistical Methods; Specific Distributions
    • C29 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables - - - Other
    • C46 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods: Special Topics - - - Specific Distributions
    • L10 - Industrial Organization - - Market Structure, Firm Strategy, and Market Performance - - - General

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