Applications of item response theory to analysis of attitude scale translations

Generalized the methods of detecting item bias developed from item response theory (IRT) to analyze the fidelity of translations of psychological scales into foreign languages. Item characteristic curves obtained from responses to the original and target language versions of the instrument were examined for significance of differences. Data from a Spanish translation of the Job Descriptive Index administered to 203 Spanish-speaking employees were used to illustrate the method. Significance tests indicated that 3 items on the 72-item instrument are biased. Subsequent inspection of these 3 items by a language consultant revealed inadequate translation of 1 item. It is concluded that the overall quality of the translation is quite good. The authors argue that equivalent item characteristic curves across the original and translated items of a scale produced equivalent measurements in both languages, and nonequivalent item characteristic curves pinpointed differences between the 2 versions of the scale. (14 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).