A scoping review of kindness measurement tools

Kindness is a domain within positive psychology that has been found to have numerous psychological benefits. However, despite the fact that kindness is an evidence-informed and cost-effective strategy to improve individuals' wellbeing, operationalizing and measuring kindness continues to be a challenge. Therefore, the purpose of this scoping review was to explore what is known from the literature regarding existing validated measurements of kindness. Our search strategy was run in three bibliographic databases (i.e., PsycINFO, MEDLINE, and SCOPUS) and yielded 2019 citations. A total of 12 articles (describing 24 studies) met the eligibility criteria and were included in this review. The Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) criteria were used to evaluate each included study. Reliability, validity, and responsiveness measurement properties were gathered and evaluated against criteria for good measurement properties. The kindness subscale within the Compassion Scale, the Kindness Scale, and the Unconditional Self-Kindness Scale were the most psychometrically sound and effective at measuring kindness, but no scale was without limitations. It is recommended that researchers develop a kindness scale that (1) clearly differentiates kindness from compassion and is (2) both inclusive and culturally competent, taking into consideration the voices of marginalized groups.