Grieder S Grob A 2020 The factor structure of the intelligence and scholastic skills domains of the Intelligence and Development Scales-2 was examined using exploratory factor analyses with the standardization and validation sample (N = 2,030, aged 5 to 20 years). Results partly supported the seven proposed intelligence group factors. However, the theoretical factors Visual Processing and Abstract Reasoning as well as Verbal Reasoning and Long-Term Memory collapsed, resulting in a five-factor structure for intelligence. Adding the three scholastic skills subtests resulted in an additional factor Reading/Writing and in Logical-Mathematical Reasoning showing a loading on abstract Visual Reasoning and the highest general factor loading. A data-driven separation of intelligence and scholastic skills is not evident. Omega reliability estimates based on Schmid-Leiman transformations revealed a strong general factor that accounted for most of the true score variance both overall and at the group factor level. The possible usefulness of factor scores is discussed. https://sonar.ch/global/documents/114665 eng info:eu-repo/semantics/altIdentifier/doi/10.1177/1073191119845051 info:eu-repo/semantics/altIdentifier/pmid/31023061 Assessment. - 2020 Cattell–Horn–Carroll Intelligence and Development Scales–2 Schmid–Leiman transformation exploratory factor analysis general factor omega coefficient Exploratory Factor Analyses of the Intelligence and Development Scales-2: Implications for Theory and Practice. http://purl.org/coar/resource_type/c_6501