A survey of missing patents at the United States patent and trademark office

Abstract

Recent articles in newspapers and magazines have suggested that many patent documents are missing from the United States Patent and Trademark Office (PTO); however, no survey has been published which attempts to verify the truth of this claim. This article reports on work undertaken to sample a number of patent classifications to determine if patents themselves are missing from the files of the PTO. The research, limited in that it can only measure patents and not patent applications or accompanying documentation, shows that missing patents are common and that each of the classifications surveyed contained missing patents. The situation may not be as bad as reported, however, in that the PTO does maintain a backup file on microfilm and Patent Depositories across the United States also maintain at least partial holdings of United States Patents on microfilm.