Unidimensional-hierarchy in value-intention scale: An application of item response theory

Item response theory was applied to Value-Intention Scale being developed on the basis of Spranger's (1966) theory according to six types of values (theoretical, economic, aesthetic, religious, social, political). Each of the six subscales corresponding to the six values made various items. Some represented extreme ideal state (ideal type) and some represented more general traits (standard type). When two parameter logistic models were applied to the subscales, if both types of items showed unidimensional, their characteristic curves were supposed to be parallel owing to differences on a difficulty level. We named such parallelism ''unidimensional-hierarchy''. From each of the six subscales, a pa ir of items unidimensional-hierarchical was selected, showing also evident differences in real response rates. Furthermore we examined the individual subjects' explanations for the responses to the items in order to clarify the contents which had determined the statistical characteristics of the items. The qualitative analysis proved that items showing higher difficulty levels contained contents harder to perform, and representing more advanced, ideal states of the value-intention.