Psychometric properties and performance of existing self-efficacy instruments in cancer populations: a systematic review

This study aims to provide a systematic compilation of existing measures of self-efficacy developed specifically for use in cancer patients and provide descriptions and comparative evaluations of the characteristics, psychometric properties and performance parameters. A systematic electronic database search was conducted in PubMed, Ovid (PsyINFO), EBSCO, Elsevier, Scopus to identify self-efficacy assessment tools for cancer patients, between January 1977 to February 2018. The characteristics of target population, instrument, development process and psychometric properties were summarized. All included instruments were subsequently appraised using a psychometric quality assessment tool based on previous publications. Validity of the quality assessment was reviewed and confirmed by five experts. Fifteen cancer-related self-efficacy instruments were identified. Among them, (40.0%) 6/15 were task-specific, focusing on cancer-related health issues such as fatigue, communication, rehabilitation, exercise, and narcotic pain killer usage. Six instruments were disease-specific for breast cancer, lung cancer, or advanced cancer. Weaknesses of the development processes included the singularity of instrument construction methods, and non-transparent selection of the final items. The main limitation seen in the validation processes was that some important properties of instruments (e.g. test-retest reliability, criterion validity, responsiveness, interpretability, feasibility, and acceptability) were not evaluated. This review summarizes the limitations and strengths of current self-efficacy instruments for cancer patient. The information reported here can assist clinicians and researchers in the selection of the appropriate instrument. Finally, it points out the need for reporting validation statistics to facilitate the use of these instruments.