Evaluating the TIS's knowledge production function using patent data: A multi-criteria approach applied to the technological bricks of the hydrogen storage

At the heart of the Technological Innovation Systems (TIS) approach is the knowledge production function. Its evaluation requires the study and characterization of the TIS knowledge base and its evolution. Although patents are often used to study this knowledge production function, current techniques for mobilizing these data can be improved. In this article, we propose to work in two directions. Firstly, most studies focus on a singular knowledge base associated with the focal TIS. However, the knowledge spaces associated with a technology are themselves plural, comprising a variety of constituent elements that must be considered separately. In this way, we have broken down the knowledge base required to develop the focal TIS into different technological building blocks. These building blocks have been classified according to three different levels of analysis: type of technological solution, challenges to be met and field of application. Secondly, most studies measure the knowledge production function by the number of patents applications. However, the sheer volume of patents is a biased indicator. A more comprehensive approach to patent analysis is recommended, based on cross-checking several indicators to ensure the accuracy of patent statistics. From this perspective, we evaluate three sets of patent indicators - persistence, commitment, and coherence - to determine, for each subset, whether there is a sufficient level of knowledge created to promote the development of the TIS. All in all, this article proposes a new method of multi-criteria analysis of the knowledge production function in four stages. The relevance and operability of this method is illustrated in the case of hydrogen storage TIS.