The number of references cited per patent continues to rise, albeit more slowly in recent years. For patents issued in 2016, the average patent includes more than 50 cited references. In my view – this is great, although it would certainly help if the examiner was given some clue as to why the reference is deemed relevant or what portion of the reference is relevant. (If an examiner has a question, they can ask the applicant). A not-surprising facet of the growth in references-cited is that almost all of the growth is in applicant-cited. Compared with 10 years ago, applicants cite 26 more references per patent (on average) while examiners cite only 1.5 more per patent. As you might also note from the difference between median and average – the citation distribution is highly skewed. Example: If we take the top-5% of patents from 2016 (those with the most references cited) – they include 35% of all of the cited references. My experience with this skew is that patent applicants considered more valuable by their owners are more likely to submit more prior art references.
Why is all this good? (1) Our IT systems can now easily handle searching through large numbers of references and in many cases the submitted references should be the first referenced searched as a group to determine a starting point for the patent analysis; (2) Because of the skew, the more important patents have more references and a better starting point. If these are well used by the examiner then we also get better examination and a stronger patent system in the end.