Center for Science and Education Management and Evaluation of Wuhan University, Chen Lixin, Zhang Lin, Huang Ying
According to the statistics of the first patentee, the average number of citations per patent in the United States is 76, 24 in Japan, 22 in China, 24 in South Korea, and 29 in Germany. It can be seen that patents in the United States have the most references, while China has the fewest references. The United States tends to provide as much relevant literature as possible, while China, Japan, and South Korea tend to provide relatively few relevant literature.
Table 194-1 Average number of patent citations in different fields in major countries in 2022
Note: The data in this table only counts the country of the first right holder (the data of China does not include patents in Hong Kong, Macau and Taiwan).
For example, in the field of medical diagnosis and surgery, 33% of patents in the United States have more or more than 100 citations to become super citation patents. This compares to only 2 percent in Japan, 1 percent in China, 3 percent in South Korea and 4 percent in Germany. Overall, 15% of patents in the U.S. are supercitations, 2% in Japan, 1% in China, 2% in South Korea, and 3% in Germany.
Table 194-2 Proportion of super-citation patents in different fields in major countries in 2022
Note: The data in this table only counts the country of the first right holder (the data of China does not include patents in Hong Kong, Macau and Taiwan).
The areas with the highest percentage of super-citation patents in the United States are: Biochemistry, Organic Chemistry, Pharmaceuticals and Cosmetics, Medical Diagnostics and Surgery, and Medical and Nursing. Between 36% and 30% of patents in these areas become super-citation patents.
The fields with the highest proportion of super-cited patents in Japan are: Pharmaceuticals and Cosmetics, Organic Chemistry, Semiconductor Integrated Circuits, Biochemistry, Display and Acoustics, and Lifestyle and Sporting Goods. Between 12% and 5% of patents in these areas become super-citation patents.
The fields with the highest proportion of super citation patents in China are: Pharmaceuticals and Cosmetics, Radio and Television and **, Railways, Ships and Aviation, Biochemistry, Life and Sporting Goods, and Organic Chemistry. Between 6% and 3% of patents in these areas become super-citation patents.
The areas with the highest percentage of super-citation patents in Korea are: Agriculture & Food, Lifestyle & Sporting Goods, Refrigeration, Heating & Lighting, Pharmaceuticals & Cosmetics, Materials Testing, Organic Chemistry, Separation & Mixing Processing, and Medical & Nursing. Between 12% and 3% of patents in these areas become super-citation patents.
The areas with the highest proportion of super-citation patents in Germany are: Pharmaceuticals and Cosmetics, Biochemistry, Display and Acoustics, Organic Chemistry, Medicine and Nursing, Agriculture and Food, Organic Polymers, and Lifestyle and Sporting Goods. Between 20% and 8% of patents in these areas become super-citation patents.
The existence of super-citation patents indicates that a very small number of patents provide a large number of citations, which is the phenomenon of over-citation of U.S. patents. In addition, the citation tendencies and citation Xi of different countries are different, resulting in a large difference in the distribution of the number of citations. If caution must be exercised when using U.S. patent citations for technical evaluation, the citations provided by a small number of patents cannot be used to evaluate most patents, and the problem of generalization may arise. The number of references for Chinese patents in the United States is small, and only a very small number of patents have more than or more than 100 references, which may not be conducive to the evaluation of Chinese patents.
We would like to thank Professor Liu Zeyuan of Dalian University of Technology, Professor Liang Liming of Henan Normal University, and researcher Wuyishan of the Chinese Academy of Science and Technology Development Strategy of the Ministry of Science and Technology for their support and help in this report. At the same time, I would like to express my sincere gratitude to the experts and scholars who have put forward their opinions and suggestions on this report in different forms.