The USPTO determines public accessibility of a document for patent purposes based on several factors outlined in MPEP 2128.01. Key considerations include: The extent of dissemination The ease with which the document can be located The intended audience's ability to find the document The MPEP provides guidance: "Whether a document is 'publicly accessible' is determined on a case-by-case basis based on the 'facts and circumstances surrounding the reference's disclosure to members of the public.'" This means that even if a document is not widely distributed, it may still be considered publicly accessible if it's available to those who would be interested in its contents and can locate it with reasonable effort. To learn more: public accessibility USPTO patent examination prior art