Within the EIDR system, dates are represented as four-digit years (yyyy) or as full dates in the form of year-month-day (yyyy-mm-dd). The full date format has the advantages of being culturally neutral (some countries list month before day, others list day before month) and being the only date format that sorts in chronological order as a text field.
- Use full dates whenever they are known.
- Use years as a fallback when the full date is not known.
- Do not use January 1 as a placeholder for an uncertain date.