The unidimensional self-efficacy scale for MS (USE-MS): developing a patient based and patient reported outcome

• Published in: Multiple sclerosis Vol. 18; no. 9; pp. 1326 - 1333
• Main Authors: Young, CA, Mills, RJ, Woolmore, J, Hawkins, CP, Tennant, A
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-09-2012; Sage Publications; Sage Publications Ltd
• Subjects: Adult; Biological and medical sciences; Chi-Square Distribution; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; England; Female; Humans; Male; Medical sciences; Middle Aged; Multiple Sclerosis - diagnosis; Multiple Sclerosis - psychology; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Neurology; Predictive Value of Tests; Psychometrics; Reproducibility of Results; Self Efficacy; Self Report; Surveys and Questionnaires; England; Rasch analysis; Psychometrics; quality of life; multiple sclerosis; patient outcome assessment; self-efficacy; Human; Nervous system diseases; Multiple sclerosis; Prognosis; Inflammatory disease; Quality of life; Unidimensional scale; Central nervous system disease; Self efficacy; Degenerative disease
• ISSN: 1352-4585; 1477-0970
• DOI: 10.1177/1352458512436592

Background:
Self-efficacy concerns the individual’s belief that he or she is capable of performing a certain task and producing a desired effect, i.e. it reflects the person’s perceptions of their capability for specific tasks, as distinct from their actual ability. Self-efficacy has been shown to influence motivation, psychological well-being, adherence with treatment regimes and quality of life in multiple sclerosis and other conditions.
Objective:
To develop a unidimensional scale of MS self-efficacy with robust psychometric properties, suitable for patient self report.
Methods:
A questionnaire pack covering three MS self-efficacy scales, the Dispositional Resilience Scale and demographic data was posted to MS patients from two MS databases. Data underwent Rasch analysis.
Results:
Response rate was 309/600 (51.5%). None of the existing MS self-efficacy scales were unidimensional. A new 12-item scale, created by combining items from our two scales, was shown to fit the Rasch model, was unidimensional, and invariant for gender, education and disease duration.
Conclusion:
The Unidimensional Self-Efficacy scale for MS (USE-MS) provides a simple summated scale for an ordinal estimate of a persons’ self efficacy. A transformation to interval scaling is available for use in the calculation of change scores and effect sizes.