Measuring a Dimension of Spirituality for Health Research: Validity of the Spirituality Index of Well-Being

Health-related studies of spirituality are threatened by the lack of conceptual distinctions between religion and spirituality, the use of small, nongeneralizable samples, and by measurement error in many instruments that unreliably and invalidly capture this domain. The authors review the construct and validity evidence for the Spirituality Index of Well-Being (SIWB), an instrument designed to measure a dimension of spirituality linked to subjective well-being in patient populations. The SIWB was developed using qualitative research methods and subsequently conceptualized with two dimensions; self-efficacy and life scheme. Primary psychometric data from three sample populations are reviewed and summarized. A secondary, confirmatory factor analysis, using pooled data from all samples, supports the theoretical two-factor structure. In addition, SIWB scores correlate more strongly with established measures of well-being than the Spiritual Well-Being Scale (SWB) or other recognized religiosity instruments. The SIWB is a valid and reliable instrument that can be used in health-related studies.