That self report may be unreliable has been suggested by other studies. Bombardier et al.
(1986) found when examining the ability of the QWB scale and other measures to detect
the effects of auranofin (oral gold) on arthritis that self-ratings by patients failed to detect
significant treatment effects that were indicated by other instruments. Tests of
self-versus-interviewer test administration have also suggested the self report can reduce
test validity (see Chapter F, section 6).