A survival analysis of patent examination request in Japanese electrical and electronic manufacturers

In this paper, we seek to identify the major determinants of the length of period between filing and examination request for Japanese patent. We consider three factors that may influence request, i.e., value index options for patent, strategy of patent filing and innovation, and environment changes faced by Japanese companies. Our sample covers over 214 listed companies in Japanese electrical and electronic manufacturing sector, and their patent applications between 1988 and 2001. The empirical results showed that, in the early 1990s, large scale firms and firms with high R&D intensity and patent propensity had a tendency to delay their request activity. But during the late 1990s, they turn to accelerate the request activity. Addition to the number of claims, some other indexes of the value of patents, i.e., originality, forward self-citation and external citation are positively related to early examination request through the most periods of our sample. And joint-application and generality show somewhat mixed effects on the request activity. Furthermore, our results revealed that including timevarying factors gave different results for the effect of the term related to competition filing.