Factorial structure of a scale: Strategies Used by People to Promote Health--Chinese version

The Strategies Used by People to Promote Health (SUPPH) is an instrument used to measure self-reported self-efficacy in patient populations. Self-efficacy has a major impact on quality of life and psychological well-being. Previous findings of dimensionality of the SUPPH vary, and cultural differences exist suggesting the need for further investigation and psychometric testing to establish construct validity of the SUPPH in different cultures.

The purpose of this study was to examine the factorial structure of the Chinese version of the SUPPH (C-SUPPH).

Using reports from 764 oncology patients in China, the factorial structure of the C-SUPPH was assessed via 2 analytical strategies. First-order confirmatory factor analysis (CFA) models were used to examine the dimensionality of the C-SUPPH; a second-order CFA was used to determine the existence of a factorial structure hierarchy of the C-SUPPH.

Compared with the 2- and 4-factor solutions, the 3-factor CFA of the C-SUPPH had a better fit with the data (comparative fit index = 0.94, Tucker-Lewis index = 0.94, root-mean-square error of approximation = 0.05, the close-fit test P = .565, and standardized root-mean-square residual = 0.04). Our findings confirmed the 3-scale structure: Positive Attitude, Stress Reduction, and Making Decisions; together, the 3 factors represent an underlying higher-order factor, that of general self-care self-efficacy.

The C-SUPPH has a valid factorial structure and can be readily applied to studying self-efficacy in Chinese patients who are diagnosed with cancers.

Our findings provide support for a culturally sensitive, reliable, and valid self-efficacy measure (the C-SUPPH) of Chinese adult cancer patients' self-care self-efficacy.