Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Eight of the included studies examined the history of changes made to each registry record in order to compare published outcomes with the primary outcome as stated in the registry at either the time of study initiation or prior to completion of enrollment [7, 16, 20, 22, 24, 30, 31, 36].
Category: