The strategies of patent introduction into patent pools

This article explores patterns of patent introduction into seven patent pools over time, analyzing 1337 essential patents. Pools grow significantly after their launch, in particular through the addition of new patents by incumbent members. The generality, width and significance of patents introduced into pools decreases significantly over time. Incumbent members file and introduce patents that are narrower, more incremental and less cited than new entrants. Pool members, however, also introduce patents relevant to larger parts of the standard.