Relationships between spirituality and health outcomes are well supported in research; however, measurement of spirituality often reflects a Judeo-Christian framework and is predominantly theocentric, neglecting the increasing religious pluralism and non-traditional expressions of spirituality in the United States. A new measure of spirituality was based on a conceptualization of nontheistic spirituality that is understood to be a relatively stable motivational process entailing a search for sacred connection, with “sacred” being defined by individual perceptions and not necessitating divine association. Item development for the current instrument included an initial pool of 65 items and two phases of revision and content validation. The resulting 45-item pool was examined for content validity via two review phases in which expert reviewers rated quality of item form and item congruence with the present spirituality conceptualization. This research addresses current measurement limitations and provides a foundation for continued revision and validation of a nontheistic-based spirituality measure.

Spirituality represents a key part of life for the majority of U.S. adults and there is a growing body of research supporting relationships between spirituality and numerous health outcomes. Governing healthcare organizations have acknowledged the role religiousness and spirituality play in comprehensive and holistic patient care. While the U.S. shows documented trends towards diverse expressions of spirituality, existing theory-driven measures of spirituality are largely theocentric. The current study concludes a multiphase project that aimed at the outset to develop an inclusive measure of spirituality and establish initial psychometric evidence, validating its use across both theistic and nontheistic spiritual populations. The Inclusive Spiritual Connection Scale (ISCS) was developed based on an expanded conceptualization of spiritual connection to include both theistic and nontheistic expressions of spirituality. The current study builds on a previous study that established preliminary evidence of content validity of the ISCS, from which a 45-item pool was developed. In the present study, data were collected from 736 participants who indicated either theistic or nontheistic sources of spiritual connection. Using a split sample approach (primary developmental sample, n = 368; secondary developmental sample, n = 368) and a test-retest subsample (n =129), the 45-item pool underwent three phases of data analysis to establish initial psychometric evidence of the ISCS for use with theistic and nontheistic populations. Through a series of factor analytic procedures, the 45-item pool was reduced to 13 items, yielding a unidimensional scale of spiritual connection with evidence of sound psychometric properties. The ISCS demonstrated adequate evidence of convergent validity, limited evidence of divergent validity, and strong evidence of reliability. Assessment of measurement equivalence across nontheistic and theistic groups yielded partial evidence of equivalence; however, the baseline levels of spiritual connection appeared to differ between theistic and nontheistic participants. Initial psychometric properties support the ISCS as a reliable and valid tool to assess spiritual connection in spiritually diverse populations, though comparison between spiritual groups requires further validation. The ISCS responds directly to existing gaps in research and possesses the ability to support holistic healthcare care for all US adults regardless of spiritual expression.