The generation of revision identifier (rsid) numbers in MS word: Implications for document analysis

The 2007 implementation of the Office Open XML standard for Microsoft Word introduced the assignation of individual revision save identifiers (risd) to document editing sessions that end in a save action. The relevant standards (ECMA and ISO/ IEC 29500-1:2016) stipulate that these rsid should be allocated randomised but with increasing numerical value, thereby documenting the progress of the editing. As MS Word is the most ubiquitous word processing software, rsid appear to be a useful tool to examine academic integrity issues in student assignment submissions (e.g. contract cheating).
This paper presents the results of a series of experiments conducted to assess whether MS Word implements the ECMA and ISO/ IEC standards. The results show that the number of allocated rsid increases with each save action, with the previous rsid carried over and retained. The newly allocated rsid do not conform to the standard as the numerical value of a rsid associated with a save action may be lower than that of the previous save action.
While rsid retain their value for document forensics as they are associated with specific edit events, the experiments have shown that they cannot be used the establishment of editing chronologies if only a single document version is in hand.