Study On Indicators Of Patent Quality

While the quantity of patents is rising sharply in the world, many countries realize a trend that the patents' quality is falling. Low-quality parents could lose competitive strength, hold back innovation, encourage more charges of infringement and litigation, also could increase social costs and waste social resources. Many developed countries have transformed their patent strategies from quantity to quality. But our country just recently began to attach important to patent quality. This shift to patent quality has set a question that how to evaluate patent quality and which indicators should be used.This paper first defines patent quality as the importance of patent's technology to form users' competitive strength, which provides fundamental base for the further research of patent quality indicators. At present, there is no uniform definition of patent quality at home and aboard. Some definitions of patent quality consider how well the patent meets the statutory substantive requirements particularly while others only emphasize one factor of legal validity, technology quality and economic perspective. This paper holds that the nature of patents is technology itself which should finally be transferred into patent products, and so the market standard of measuring patents' technology quality is how well the patent will make the user have a competitive advantage. Therefore, this paper defines patent quality from view of competitive strength. This definition is a broad and relative concept which focuses on all factors of legal, technology and economy.Secondly, this paper theoretically sets up patent quality indicators and verifies their efficacy. As the existing indicators is complicated, this paper divides them into four fields about patent citation, patent renewal, patent scope and others, and analyzes their meaning, principle and efficacy. This paper also finds some defective indicators and attempts to amend them or design new ones. This paper chooses some reasonable indicators, including patent references, non-patent references, self-backward paper citations, forward citations, science linkage, technology cycle time, generality index, "whether renew at the 8^th (5^th ) year after patent grant", patent family size or "whether have a patent family", number of claims, technology scope and number of inventors. As for these indicators, based on samples of Chinese award-winning patents and patents that China got from USPTO, this paper first verifies the efficacy of some individual indicators through mean comparison and removes the indicators that have no relation to patent quality, and then verifies all of the rest indicators through logistic regression and finally confirms three efficiency indicators, including forward citations, number of claims and number of inventors.Finally, this paper structures a model of patent quality index and gives examples for measuring patent quality with it. Based on the three efficiency indicators, this paper regards standard regression coefficients in logistic regression as weight of indicators, transfers initial data of indicators into relative index by the way of fixed-effect, and structures the model of patent quality index with linear weighted comprehensive assessment method. The index can evaluate quality of single patent and multiple patents, and free from grant year and technology field. Furthermore, the index not only can horizontally or vertically compare the differences of patent quality of evaluated objects, but also can judge the relative level of patent quality of evaluated objects in the system. In addition, this paper gives examples for measuring quality of single patent and multiple patents with the index, and demonstrates the applicability of the index.