Invention never happens in a vacuum, and instead tends to build on earlier work done by either the inventor or other inventors. It is possible to track this 'knowledge flow' by looking at patent citations, which may be among the most reliable sources of innovation related data. While some other patent analysis techniques also analyse patent citations, NPA adds two improvements to this process:
- Only citations between patents in the study of interest are considered. Some broad patents have disclosures that may be relevant to a number of different fields. However, NPA is focused on finding the strongest patents within a specific field of interest, and so only takes relevant patent citations into account.
- In any case, patent citations are not treated equally. NPA has a process for weighting patent citations, and these weighted patent citations are used when assessing the relative importance of patents.
There are many other potential applications for knowledge flow analysis, including patent litigation. In the recently released report Clearing the fog: Patenting trends for the treatment of Alzheimer's disease, we have investigated which patents have had the strongest influence on other patents in this field. Clearing the fog identifed 23 clusters of patenting activity, which in turn formed into two groupings of clusters, which we names the Amyloid Grouping and Tau Grouping in relation to the proteins these patents were targeting. The top three foundation patents, or most influential, in each grouping of clusters is shown in the Table.
This table shows some interesting results. The most influential patent in the Amyloid Grouping, the now expired US4666829 filed by the University of California, discloses the Alzheimer's Amyloid Polypeptide (AAP) which is the precursor of beta amyloid, and had 94 forward citations in the dataset. The next most influential patent was the number one ranked NPA patent of all.
It should be noted that this type of analysis should not be confused with the general NPA patent ranking process, which also takes into account other measures of patent 'popularity'. Nonetheless analysis of foundation patents can help provide a unique perspective on the history of a technology, and its key influences and influencers.
(This blog post was based on material previously presented in the Clearing the fog report: used with permission)