Jc3s5h added a comment. As far as I can tell Wikidata's statement to data contributors and users about the meaning of dates stored in Wikidata is at [[mw:Wikibase/DataModel/JSON]]. The [ earliest version] dated 29 April 2014 states "time: Date and time in ISO notation". The 2004 version of ISO 8601 defined 0000 as 1 BCE, contrary to XSD 1.0. Furthermore, [[en:astronomical year numbering]], which was probably the most common use of negative years before the late 20th century proliferation of computer standards, treats 0 as 1 BCE.
I believe we must presume that most data contributors have not read all the code that implements Wikibase, and just believed the statements, and the general public understanding of what the year 0 is. More importantly, they would understand year (-n) to be equal to year (n+1) BCE. What would get stored in wikibase would depend on how it was entered; the user interface would have changed an input of "5 BC" to -5, but using an API to enter "-00000000004-12-31T00:00:00Z" (which the data contributor would have regarded as equal to 31 December 5 BC) as-is. **This means that every year <= 1 AD in the database is suspect and must be reviewed for correctness**. TASK DETAIL https://phabricator.wikimedia.org/T94539 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: Jc3s5h Cc: Jc3s5h, JanZerebecki, Manybubbles, Thompsonbry.systap, Haasepeter, Beebs.systap, Aklapper, Smalyshev, jkroll, Wikidata-bugs, Jdouglas, aude, daniel _______________________________________________ Wikidata-bugs mailing list Wikidata-bugs@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-bugs
