Measurement Properties of the Low Back Activity Confidence Scale (LoBACS)

The purpose of this study was to determine the measurement properties of the Low Back Activity Confidence Scale (LoBACS) in individuals with post-acute low back pain (LBP) receiving nonsurgical intervention, including construct validity, factorial validity, and internal consistency reliability. Data were analyzed from an existing randomized clinical trial involving 112 patients with LBP. Evidence for convergent validity was observed through significant correlations between LoBACS subscale scores and other function, pain, and psychobehavioral measures. LoBACS subscales accounted for 36% of the unique variance in dependent variable measurements, suggesting a satisfactory level of statistical divergence between the LoBACS and other psychobehavioral measurements in this study. Cronbach's α ranged from .88 to .92 for LoBACS subscales, and item-total correlations exceeded .6, indicating high internal consistency reliability. Principal axis factoring confirmed the hypothesized three-subscale structure by correctly classifying 14 of the 15 items. These findings indicate the LoBACS is valid and internally consistent to measure domain-specific self-efficacy beliefs.