For an attribute with a recency survivorship rule which has sources with the same update date, which value survives?
The recency rule will choose the value that has most recently been contributed to the attribute. More accurately, the rule will find the most recently contributed value, identify the crosswalk that contributed that value, and then use all the values contributed by that crosswalk.
The crosswalk responsible for a value (or set of values) in the attribute has a LUD date associated with it. However, a value itself also carries its own local LUD. The recency rule looks first at the LUDs of the values when finding the most recent value. If none are more recent than the LUD of its parental crosswalk, then the LUD of the crosswalk is used and compared against the LUD of the other crosswalks to find the most recent crosswalk and, thus, in effect, find the most recent value to use.
The recency rule considers three dates - Update date, sourcePublishDate, and individual attribute update date. It uses all three of them and chooses the most recent from them to apply the date in the crosswalk.