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:To analyze the statistical correlation between measures of the CT and schizophrenic psychopathology (measured by PANSS), we calculated a Spearman rank correlation within the first-episode schizophrenia (or SZ) patient group.
Category: