Numbers and sizes of applicants at the European Patent Office

The evolution of numbers of applicants and the applicant size distributions in terms of numbers of patent filings are described for clients of the European Patent Office (EPO). Concentrating firstly on the period from 1999 to 2006, it is found that only about 35% of the applicants that file in one year then file again in the following year. However this percentage does not drop too much in further years because of a core group of large companies that persist in making considerable numbers of filings. It is mainly the applicants with small numbers of filings in a year that apply intermittently. A historical analysis is made since 1980 on applicant sizes in terms of Total filings. Breakdowns of the counts are considered by using a series of Size groups. The dynamics are studied via simple Markov chain stochastic process models for transitions between the Size groups. These involve a no-memory-assumption for approximating the probabilities of transitions for two and more years. Firstly, a general model is fitted. This allows a direct estimation to be made of the average remaining lifetime of continuous filing for an applicant that is already active. Then a "poisoned" model is fitted in which no further transitions are allowed back to filing after an applicant ceases to file. Finally, a five year windowed approach is taken to remove the influence of inactive applicants on the transition probabilities as far as possible. A comparative test suggests that the poisoned approach works best among the models that were tested. The discussion section considers policy implications and suggests ways to further develop the approach.