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:Compounding this limitation, the WSAP did not result in an equal number of data points (i.e., reaction times) for each type of wordsentence pair (Amir et al. 2012; Beard and Amir 2009).
Category: