The Pain Self-Efficacy Questionnaire (PSEQ) is used by physiotherapists clinically as well as in research. However, understanding of the PSEQ’s measurement properties is incomplete at present, such that we cannot be confident it provides unbiased information on an individual’s self-efficacy. The authors’ objective was to study the scale properties of the PSEQ using Rasch analysis. They attempted to determine whether age, gender, pain severity, pain duration and pain-related disability bias the function of the PSEQ as well. The study was retrospective, using data obtained from three existing studies. Data were combined from over 600 patients with low back pain of varying duration. Rasch analysis was used to evaluate targeting, category ordering, unidimensionality, person-fit, internal consistency and item bias. They provide evidence of adequate category ordering, unidimensionality and internal consistency of the PSEQ. Significantly they found no evidence of item bias. They noted that PSEQ did not adequately target the sample, targeting instead people with lower self-efficacy than this population. Item 7 was hardest for participants to endorse, showing excessive positive misfit to the Rasch model. Response strings of misfitting persons revealed older participants and those reporting high levels of disability.
The authors concluded that individual items of the PSEQ can be validly summed to provide a score of self-efficacy that is robust to age, gender, pain severity, pain duration and disability. While item 7 is the most problematic, it may provide significant clinical information and needs additional investigation before its exclusion. Although the PSEQ is commonly used with people with low back pain, of whom their sample was representative, their results suggest it targets patients with less self-efficacy than that observed in their sample.