Patent quality: Putting the patent in the h-index


Patent quality: Putting the patent in the h-index

Most academics are familiar with the h-Index which is an author-level citation metric to measure the productivity and citation impact of a scientific publication. The Index, developed by the physicist Jorge Hirsch, is based on a scientist’s most cited papers and has become a globally-recognized indicator of research quality.


There’s so much talk about patent quality, all this got us to thinking: what about the “p-IndexTM”? Where the h-Index can tell us something about the productivity and influence of an academic researcher, is there anything that the p-IndexTM can tell us about the productivity and influence of Australian inventors on published patent rights. We think that the p-IndexTM could become a global measure of inventor quality.


At IP Solved, we have calculated the p-IndexTM for Australian inventors. Its calculation has been undertaken in substantially the same way as for the traditional h-Index, only an inventor’s most highly-cited patent rights have been ranked and analyzed. The results are shown below.


It might not be surprising to some to see that Kia Silverbrook tops the list with a p-IndexTM of a whopping 92. Kia is followed by his colleague Paul Lapstum with a p-IndexTM of 66. Also in the list are some of Australia’s most influential polymath inventors as listed in our previous article.


The P-Index for top Australian inventors

 pindex pic


We searched for inventions published in the name of recently-active Australian inventors, so this list is not exhaustive and simply represents the inventors that were subject to a search. If you think that your name should be on the list, or you simply wish to know your own p-IndexTM please get in touch.




We used the Derwent Innovation patent database hosted by Clarivate Analytics (formerly Thomson Reuters). In order to create a starting list of inventors most likely to have a high p-IndexTM, we looked for Australian inventors holding 5 or more influential inventions (citation count > 10) published in the last ten years (EPY > 2007). Each of those inventors was then searched individually in order to create an inventor dataset for analysis.


In order to calculate the p-IndexTM:


  1. Total Count: We only exported datasets in which the inventor held 10 or more patent rights (N > 10).
  2. Ranking by Citation Count: We ranked the patent rights for each inventor by DPCI* Citation Count from highest to lowest.
  3. Calculating the p-IndexTM: Where n is the function that corresponds to the number of citations for each patent right, we looked for the last position in the rank where n was greater than or equal to the ranked position. For example, if we have an inventor with 5 patent rights A-E with 300, 250, 10, 3, 1 citations respectively, the p-index is equal to 3 because the 4th patent right has only 3 citations and 3 < 4. n(A)=300, n(B)=250, n (C)=10, n(D)=3, n(E)=1 p-indexTM=4



  1. The data shown is for inventors that were subject to a search. There may be other inventors that could be added to the list with high p-IndexTM values.
  2. We searched for inventor names as we found them most commonly in the database. There may be other spellings for an inventor’s name that have been missed resulting in loss of some of their rights for analysis.
  3. Inventors with a p-IndexTM < 10 are not shown here. {\displaystyle \max _{i}\min(f(i),i)}


*we used the Clarivate Analytics Derwent Patent Citation Index (DPCI®), which is a superior citation analysis tool. Some notes on citation analysis using DPCI: A patent can be granted for an invention that is (amongst other things) new and not obvious. As a patent application passes through the patent system it will be examined by the Patent Office for (amongst other thing) how new and non-obvious it really is. During that examination process, an invention may be found to be similar (X/Y) or the same (X) as technology already available in the published literature. The patent application under examination may attract some “Examiner citations” from the published art that are effectively obstacles to the patent applicant going on to achieve patent protection. The citations accrue against an invention. The citations are de-duplicated by DPCI® to ensure that there is no double counting as multiple family members of an invention pass through the system.


  • by Nicola Maxwell, Principal, Head of Engineering, Registered Patent Attorney

A version of this article first appeared on LinkedIn on 21 November 2017.

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