Performance comparison between IB and Non-IB students on the International Schools’ Assessment: Applying Hierarchical Linear Modelling to the 2023 and 2024 data

This report compares the academic performance of International Baccalaureate (IB) students in the Primary Years Programme (PYP) and Middle Years Programme (MYP) with that of students in other accredited international schools, using data from the International Schools’ Assessment (ISA). The ISA is designed for students in international schools from grades 3 to 10 and evaluates proficiency in five domains: Mathematical Literacy, Reading, Scientific Literacy, Narrative Writing and Expository Writing. In addition, ISA scales for Mathematical Literacy, Reading and Scientific Literacy are based on the internationally recognized frameworks used in the Organisation for Economic Co-operation and Development’s (OECD) Programme for International Student Assessment (PISA), allowing for robust benchmarking and international comparability. This study replicates previous research (Tan, Bibby, 2010; Tan, Bibby, 2012; ACER, 2021), using more recent ISA (2023–2024) and PISA (2022) results.