Background. Spiritual beliefs are rarely considered in psychological or med
ical publications. We recently published the psychometric properties of an
interview designed to measure religious and spiritual belief. In this study
, we aimed to develop this instrument further as a self-report questionnair
e and to make it more comprehensive by including measurement of spiritual e
xperiences in addition to faith or intellectual assent.
Methods. Based on extensive discussion with colleagues, advice from users o
f the interview and comments from respondents, a self-report format was des
igned. We then evaluated the final format of the questionnaire in terms of
(1) patterns of response and demographic predictors of beliefs; (2) test-re
test reliability and internal consistency; (3) criterion and internal valid
ity; and (4) the nature of spiritual experiences and their relationship to
beliefs and strength of beliefs.
Results. Two hundred and ninety-seven people took part in the validity and
reliability tests of the questionnaire. Criterion validity, predictive vali
dity, internal consistency and test-retest reliability were acceptably high
. The instrument consistently differentiated between people with high and l
ow spiritual beliefs.
Conclusions. This instrument is brief and simple to complete. We would reco
mmend that measures of religious and/or spiritual belief like this be more
widely applied in health services research as they evaluate aspects of peop
le's lives that go somewhat further than health status or quality of life.