Jo. Lanjouw et al., HOW TO COUNT PATENTS AND VALUE INTELLECTUAL PROPERTY - THE USES OF PATENT RENEWAL AND APPLICATION DATA, Journal of industrial economics, 46(4), 1998, pp. 405-432
Patent counts are very imperfect measures of innovative output. This p
aper discusses how additional data-the number of years a patent is ren
ewed and the number of countries in which protection for the same inve
ntion is sought-can be used to improve on counts in studies that requi
re a measure of the extent of innovation. Simple weighting schemes are
proposed, which may remove half of the noise in patent counts as a me
asure of innovative output. We describe models of the patent applicati
on and renewal processes whose parameter estimates can be used to asse
ss the value of the proprietary rights created by the patent laws. We
illustrate their use with estimates of how the value of patent protect
ion would vary under alternative legal rules and renewal fees and with
estimates of the international flows of returns from the patent syste
m. Recent progress in the development of databases has increased the p
otential for this type of analysis.