Provision of a date (eg date of birth) is often a mandatory requirement in data collections. Often it must be recorded in a date field type, in a computer system which does not allow the recording component of the date as null. At times, the actual date or part thereof may not be known. This data element is intended to be designed to flag a date that has been estimated, and indicate the level of accuracy with which the date is known. This data element may assist with record linkage processes when the date of birth is a component of the linkage key.