Measuring patient anxiety in primary care: Rasch analysis of the 6-item Spielberger State Anxiety Scale.

ABSTRACT

OBJECTIVES: The 6-item Spielberger State Anxiety Scale has been used as a replacement of the original version in many health-care studies. The purpose of this study was to evaluate the measurement properties of the shortened 6-item Spielberger State Anxiety Scale using Rasch analysis in general medical practice patients (N=297). METHODS: Participants (aged 16 years or above) were recruited on a consecutive basis from three general medical practices. Prior to their appointment, participants were asked to complete a 6-item Spielberger State Anxiety Scale. RESULTS: The results of the study showed that the scale is unidimentional, and each item measures a different level of patient anxiety. The rating scale operated well and item and person reliability was good. Furthermore, principal-components analysis of the residuals confirmed the scale measures a unitary concept. A scoring key was generated to allow conversion of raw scores to a continuous measurement. CONCLUSION: The 6-item Spielberger State Anxiety Scale is shorter than the original version and has good psychometric properties. This would suggest the scale is a valid alternative to the full version for use in primary health-care practice and research.