Abstract

The use of polytomous items as part of background or context questionnaires and complex sampling designs are two features common in international large-scale assessments (ILSA). Popular choices to model polytomous items within ILSA include the partial credit model, the graded response model, and confirmatory factor analysis. However, an absent model in ILSA studies is the continuation ratio model. The continuation ratio model is a flexible alternative and a very extendable response model applicable in different situations. Although existing software can fit this model, not all these tools can incorporate complex sampling design features present in ILSA studies. This study aims to illustrate a method to fit a continuation ratio model including complex sampling design information, thus expanding the modelling tools available for secondary users of large-scale assessment studies.