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:Secondly, the results provide quantitative evidence regarding the difficulty of conveying privacy related functions and policies to users; earlier research has shown that users often do not read such policies [17, 19] or are not able to comprehend them [15, 19].
Category: