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Lanjouw Schankerman (2004) - Protecting Intellectual Property Rights (view source)
Revision as of 15:11, 22 June 2016
, 15:11, 22 June 2016no edit summary
disadvantage in protecting their patent rights since their greater litigation risk is not
offset by more rapid resolution of their suit.
== Objectives of the paper==
# Identify the main empirical factors that determine which patents are litigated.
# To understand whether small firms with a small patent portfolio are handicapped in the process of protecting their intellectual property rights.
==Data==
===Small vs. large firm===
Listed firms are classified under:
* Large firms: employment above the median of 5,425.
* Small firms: employment below the median.
===Litigated patents===
Identified from the LitAlert database produced by Derwent(private vendor).
* 13,625 patent cases filed during 1978-99, each identifying the the main patent in dispute
* 9,345 are involved in the sample of suites
* Derwent data matched to all U.S. patent related cases, code 830. (Federal Judicial Center, Federal Court Cases: Integrated Data Base, 1970-89 (1999))
===Control group and control variables===
*Matched set of patents as control group:
**For each litigated patent, another was chosen at random from the set of all patents with the same application year and primary three-digit USPC assignment(thus controlling for technology and cohort effect).
* For each litigated and matched patent the following characteristics
# Nationality of the patent owner \\
# Technology field: the first assigned USPC class
+ Number of claims: higher claim number associated with greater patent value and thus more disputes. !!!
+ Citations
+ Ownership: Individual, listed/unlisted company.
+ Patent portfolio size: grouped into 1-100 100-900 >900
+ Relative size of potential disputants: measure of the asymmetry in portfolio size between a patentee and a
representative disputant he can expect to face on each patent.
Let $Z_{cf}$ be the portfolio size for firm $f$ in technology class $c$, and let
$Z_c = \sum_f Z_{cf}$ denote all patents in the class.
$Z_f = \sum_c Z_{cf}$ is the portfolio size for firm $f$
$Z_c^* Z_c / n_c$ is the average portfolio size of the $n_c$ firms with patents in class $c$.
The relative portfolio size of firm $f$ for patent $ i$ is given by:
$R_{if} = Z_f /\sum_c w_{ci} Z_c^*$, where $w_ci = F_{ci}/F_i$ is the fraction of forward citations to
patent $i$ that falls into technology class $c$.
+ Technology concentration
