Scaling Procedures for ICILS Questionnaire Items

This chapter describes the procedures used to scale the ICILS questionnaire data (for students, teachers, school principals, and ICT coordinators) and the indices based on them. Two general types of indices could be distinguished, both of which derived from the ICILS questionnaires: 1. Simple indices constructed through arithmetical transformation or simple recoding, for example, ratios between ICT and students or an index of immigration background based on information about the country of birth of students and their parents; and 2. Scale indices derived from scaling of items, a process typically achieved by using item response modeling of dichotomous or Likert-type items. The first part of this chapter describes the simple indices derived from the ICILS questionnaire data and the procedures applied to create them. The second part outlines the scaling procedures used in ICILS. The third and final part provides a detailed description of scaled indices, along with statistical information on item parameters, scale reliabilities, and the factor structure of related item sets.