Development and Validation of the Single-Item Mindfulness Scale (SIMS).

Mindfulness is a focused attention to and acceptance of present experiences. Although several reliable and valid multi-item measures of trait mindfulness exist, researchers may sometimes want a short and quick measure of mindfulness. In this project, we developed and validated the Single-Item Mindfulness Scale (SIMS) to assess trait mindfulness. We conducted eight studies involving 3,125 adult and adolescent participants. The studies consisted of cross-sectional, short longitudinal, and daily diary designs. We first developed the wording of the SIMS in Studies 1 and 2 and then examined the validity and reliability in Studies 3-8. The SIMS was found to be reliable and valid. It correlated with several multi-item measures of mindfulness at effect sizes in the medium to large range. It also correlated in expected ways with variables known to be related to existing multi-item measures of mindfulness such as self-compassion, anxiety, negative affect, positive affect, depression, neuroticism, empathy, prosocial behavior, and self-consciousness. Furthermore, it correlated positively with daily reports of mindfulness in a two-week diary study. Although existing multi-item trait mindfulness scales should be used, when possible, the SIMS is recommended in situations when time, question quantity, or researcher focus is constrained.