Questions addressing the extent to which pain interferes with activities ask about general activity, mood, walking ability, normal work relations with other people,
sleep, and enjoyment of life. As interference with work was not applicable in this study, we substituted interference with exercise for that one item. However,
this modification did not reduce the reliability of BPI Pain Interference in this sample (see reliability statistics reported in the Results section). Patients rate the extent to which pain interferes with activities on a 0–10 scale with 0 representing no interference and 10 representing
total interference or the inability to perform the activity
due to the severity of the pain