Chapter 6: Science & Engineering Indicators 93
Highly Cited InventionsDuring the 1981-85 period, the seven countries together created 2,043 optical fiber patent families, of which 22 were highly cited. (Click here for footnote 57.) Japan generated the greatest number of patent families in this technology area during this period and also had the greatest number of highly
cited inventions--12 (or 54 percent of all highly cited patent families). Yet, when each country's number of highly cited patent families is normalized by calculating its citation ratio, the United States leads all seven nations. The United States
had a citation ratio of 2.0, or two times as many highly cited patent families than would be expected given its share of total families during this period. Japan's citation ratio, 0.9, suggests that the 12 highly cited families produced by Japan
during this period were slightly below expectations, given the total number of patent families generated by Japan. Great Britain had only one highly cited family, but meets expectations in this indicator
with a citation ratio of 1.0. (See text table 6-11 and appendix table 6-27.)
In the 1986-90 time period, the number of optical fiber inventions (patent families) doubled, and the number of technically important patent families were over three times that recorded during the earlier period. Japan accounted for nearly 69 percent
of the patent families generated in this period, but again did not produce the expected number of highly cited families out of this total. It ended up with a citation ratio of only 0.5. With a citation ratio of 2.6, the United States once again shows
high productivity of technically important optical fiber inventions.
Several European countries showed greater productivity of technically important optical fiber inventions in the late 1980s. Great Britain stands out in this later period, with a citation ratio of 3.5, the highest among the seven countries. France,
with a citation ratio of 2.9 during this period, also greatly exceeds expectations, producing nearly three times the number of highly cited families expected from its total number of optical fiber inventions patented during this period.
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