The Functional Assessment of Chronic Illness Therapy–Spiritual Well-Being (FACIT-Sp) scale is a valid and reliable instrument to provide an inclusive measure of spirituality in research and clinical practice. The aim of this study was to translate and investigate the reliability and validity of the Persian version of the FACIT-Sp.

The 12 item spiritual well-being subscale of the FACIT-Sp Version 4 was translated into the Persian language, Farsi, using the FACIT translation methodology. The questionnaire was administered to a diverse sample of 153 patients in treatment for cancer. Internal consistency was assessed by Cronbach's α coefficient, confirmatory factor analysis (CFA) was applied to assess construct validity, and regression analysis was used to assess the predictor role of the FACIT-Sp in health-related quality of life (HRQOL).

Cronbach's α reliability coefficient for the FACIT-Sp subscales ranged from 0.72 to 0.90. The CFA generally replicated the original conceptualization of the three subscales of the FACIT-Sp12 (Peace, Meaning, and Faith). All three subscales significant predicted HRQOL.

The Persian version of the FACIT-Sp scale is a reliable and valid tool for the clinical assessment of, and research into, the spiritual well-being of Muslim Iranian and Farsi-speaking patients in other regions of the world who are in treatment for cancer.

With increasing research on the role of religion and spirituality in the well-being of cancer patients, it is important to define distinctly the concepts that researchers use in these studies.

Using the philosophies of Frege and James, this essay argues that the terms “religion” and “spirituality” denote the same concept, a concept that is identified with the Peace/Meaning subscale of the Functional Assessment of Chronic Illness Therapy — Spiritual Well-being Scale (FACIT-Sp).

The term “Religions” denotes the concept under which specific religious systems are categorized.

This article shows how muddling these concepts causes researchers to make claims that their findings do not support, and it ends in suggesting that future research must include universal measures of the concept of religion/spirituality in order to investigate further the role of interventions in the spiritual care of people living with cancer.