A survival analysis of the approval of US patent applications

We model the length of time that it takes for a patent application to be granted by the US Patent and Trademark Office (USPTO), 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 analyse 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 nonmonotonic over time.

[1]  D. Freedman.  Survival Analysis , 2008 .

[2]  Tony Lancaster,et al.  The Econometric Analysis of Transition Data. , 1992 .

[3]  N. Kiefer.  Economic Duration Data and Hazard Functions , 1988 .

[4]  Stephen Nickell,et al.  Estimating the Probability of Leaving Unemployment , 1979 .

[5]  N. Kiefer,et al.  How Long is a Spell of Unemployment?: Illusions and Biases in the Use of CPS Data , 1984 .

[6]  Adam B. Jaffe,et al.  Reinventing Public R&D: Patent Policy and the Commercialization of National Laboratory Technologies , 2001 .

[7]  R. Frank.  How Long Is a Spell of Unemployment , 1978 .

[8]  Stephen A Merrill,et al.  Patents in the knowledge-based economy , 2003 .

[9]  Hal S. Sider.  Unemployment Duration and Incidence: 1968-82 , 1985 .

[10]  H. Tao,et al.  The impact of sectoral shifts and the aggregate labour market on unemployment duration , 2007 .

[11]  Daniel K. N. Johnson,et al.  Time In Purgatory: Examining the Grant Lag for U.S. Patent Applications , 2004 .

[12]  David E. A. Giles,et al.  Modelling the duration of interest rate spells under inflation targeting in Canada , 2009 .

[13]  C. Granger.  Some Methodological Questions Arising from Large Data Sets , 2003 .

[14]  R. Michael Alvarez,et al.  Event History Modeling: A Guide for Social Scientists , 2004 .

[15]  Donald R. Haurin,et al.  The impact of local unemployment rates on reservation wages and the duration of search for a job. , 2003 .

[16]  Christopher Cox,et al.  The generalized F distribution: An umbrella for parametric survival analysis , 2008, Statistics in medicine.

[17]  E. Kaplan,et al.  Nonparametric Estimation from Incomplete Observations , 1958 .

[18]  G. Grossman,et al.  Innovation and growth in the global economy , 1993 .

[19]  Manuel Trajtenberg,et al.  Patents, Citations, and Innovations: A Window on the Knowledge Economy , 2002 .

[20]  John Kennan,et al.  The duration of contract strikes in U.S. manufacturing , 1985 .

[21]  S. Sosvilla‐Rivero,et al.  Regimen Changes and Duration in the European Monetary System , 2003 .

[22]  Adam,et al.  Flows of knowledge from universities and federal laboratories: modeling the flow of patent citations over time and across institutional and geographic boundaries. , 1996, Proceedings of the National Academy of Sciences of the United States of America.