What is a unique feature of the IEA's approach to testing?

The unique feature of the IEA's approach to testing is the inclusion of contextual questionnaires alongside the main assessments. This method enables a deeper understanding of the factors influencing educational performance beyond mere test scores. By incorporating these questionnaires, the IEA can gather information on student backgrounds, learning environments, and teaching practices, thereby providing a more comprehensive analysis of educational outcomes. This holistic approach allows researchers and policymakers to examine not just what students know, but also how different variables contribute to their performance, making the assessment process more insightful and valuable for educational research.