Psychometrically relevant population differences may limit the transferability of research instruments between migrants and their source population and may contribute to a low performance of quantitative questionnaires. Based on a review of existing taxonomies, this book develops a comprehensive analytical framework of equivalence that can serve multiple purposes. It allows to examine psychometrically relevant population differences, it can assist in the re-adaptation of questionnaires and it is a valuable tool for cross-group comparative research. The application of the framework is illustrated through the examination of equivalence of the Revised Illness Perception Questionnaire (IPQ-R) between chronically ill Turks residing in Turkey and Turkish migrants residing in Germany.

Psychometrically relevant population differences may limit the transferability of research instruments between migrants and their source population and may contribute to a low performance of quantitative questionnaires. Based on a review of existing taxonomies, this book develops a comprehensive analytical framework of equivalence that can serve multiple purposes. It allows to examine psychometrically relevant population differences, it can assist in the re-adaptation of questionnaires and it is a valuable tool for cross-group comparative research. The application of the framework is illustrated through the examination of equivalence of the Revised Illness Perception Questionnaire (IPQ-R) between chronically ill Turks residing in Turkey and Turkish migrants residing in Germany.