Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This study analyses the patent trends and volatilities for the top 12 foreign patenting countries in the US market from 1975 to 1997. Japan is ranked first in terms of foreign patents registered in the USA, followed by Germany. Patent registrations from each of these countries have increased steadily over time, but at different rates. Using monthly time series data for 1975-1997, the time-varying volatility of Australian, Japanese and German patents registered in the USA is examined in detail. The asymmetric AR(1)-GJR(1,1) model is found to be suitable for Australia and Japan, while the best fitting model for Germany is the symmetric AR(1)-GARCH(1,1) model.