Psychometric validation of the S-QoL Chinese (Taiwan) version for patients with schizophrenia

We translated the S-QoL into the Chinese (Taiwan) language and evaluated the score distributions of the translated S-QoL in terms of ceiling/floor effect, internal consistency, test-retest reliability, and convergent and discriminant validity. To ensure conceptual and semantic equivalence of the S-QoL, the researchers performed both forward translation and back translation, consulted professionals, and completed a pilot trial on college students. Forty-one patients with schizophrenia were recruited. No significant ceiling/floor effects (< 20%) were found in subscales of the translated S-QoL. The internal consistency reliabilities were acceptable to good for the whole scale and 7 of the subscales (Cronbach's alpha = 0.71-0.93), but not for the sentimental life subscale (Cronbach's alpha = 0.44). The test-retest reliabilities were moderate to high (ICC = 0.64-87, P < 0.001 to < 0.0001). The convergent validities were supported by satisfactory correlations among subscales measuring related constructs of the translated S-QoL and those of the SQLS-R4, WHOQoL-BREF, and RESE (r = 0.36-0.82, P < 0.05 to < 0.01). Discriminant validity was demonstrated between groups with different numbers of episodes and hospitalization. The S-QoL Chinese (Taiwan) version was found to have good psychometrics and is suggested as a feasible choice of disease-specific measure for capturing HRQoL in patients with schizophrenia.