SF-36 health survey: Tests of data quality, scaling assumptions, and reliability in a community sample of Chinese Americans

BACKGROUND. Chinese Americans are one of the fastest growing ethnic groups in the United States; however, language and cultural obstacles have challenged health workers and policy makers seeking to understand the health status and needs of this population. OBJECTIVES. This study is the first to use a large-scale probability design to evaluate the 36-item Short-Form Health Survey (SF-36) in a Chinese population (n = 1,501). METHODS. Using the International Quality of Life Assessment Project protocols, we examine summated-rating scaling assumptions, item-internal consistency, item-discriminant validity, and reliability. RESULTS. Similar to previous studies, our tests indicated that the SF-36 generally met minimum psychometric criteria with high reliability and satisfactory scaling success rates for most scales. However, the performance of the vitality and mental health scales was less satisfactory with regard to discriminant validity and scaling success rates. Notably, our results indicate that VT3 and VT4 ("feel worn out" and "tired," respectively) formed a separate "fatigue" cluster more highly correlated with the mental health scale. However, MH4 and MHS ("downhearted and blue" [reverse coded] and "been a happy person") were more highly correlated with the vitality scale, suggesting that it may be more meaningful to reorganize the vitality and mental health items along the dimensions of well-being and distress. CONCLUSIONS. These results are interpreted within a cultural framework; however, additional work is needed to better understand the relationship between vitality and mental health for Chinese Americans.