Extension talk:Wikibase Quality Extensions/Archive 1

Birth dates
I notice you plan to compare birth dates to external databases as a quality control measure. However, there are bugs in Wikidata's implementation of birth and death dates. One part of the discussion is at https://phabricator.wikimedia.org/T88438

The last country to change from the Julian to the Gregorian calendar was Greece in March 1923. Before that, it is difficult to decide if a date is in the Gregorian or Julian calendar. Also, at the moment, Wikidata does not have a policy about whether dates of events that occurred at a time and place where the Julian calendar was in force should be stored in the Julian or Gregorian calendar. Also, there is no policy about what format the date should be stored in.

Another pitfall is for dates in ancient Rome, which were recorded in the Roman calendar. Not enough records survive from ancient times to precisely convert Roman calendar dates to either proleptic Julian or Gregorian calendar dates. Also, between 45 BC and 1 March AD 4, the Julian calendar was not implemented as Julius Caesar intended, so conversion of these dates to the proleptic Julian or Gregorian calendars may be wrong by a few days. (Proleptic means that one starts from a well known modern date and applies the rules of the calendar to give dates to events before the calendar was introduced.) Jc3s5h (talk) 15:56, 19 February 2015 (UTC)