This book is the world’s first comprehensive and unified textbook on cognitive diagnostic models (CDMs), integrating theory, application, and full software implementation within a single coherent framework. Unlike existing works that focus on isolated models, technical details, or fragmented case studies, this volume provides a standard, accessible, and self-contained introduction to the field. In that way, it substantially lowers the barrier to entry for newcomers while remaining rigorous enough for advanced readers.

At the heart of the book is a unified perspective on CDMs as latent variable models designed to identify fine-grained mastery profiles of cognitive attributes underlying test performance. Moving beyond overall test scores and continuous proficiency scales emphasized in traditional item response theory, the book explains how CDMs rely on categorical latent structures that represent mastery and non-mastery of specific skills. These concepts are presented intuitively and conceptually, with minimal reliance on advanced mathematics, making the material approachable for educators, graduate students, and applied researchers.

A distinctive feature of this volume is its strong emphasis on practical implementation. All methods and examples are fully implemented in the R language, allowing readers to immediately apply CDMs in real educational and research settings. Step-by-step illustrations guide users through model specification, estimation, interpretation, and diagnostic reporting. By combining interpretability, methodological coherence, and hands-on applicability, this single volume offers a comprehensive understanding of cognitive diagnostic models and their use in educational and psychological measurement.

As a psychometrician and an expert in structural equation modeling, the author has calculated the brand value of Brand Japan since the first survey. Brand Japan is a brand value evaluation project sponsored by Nikkei BP Consulting, which has been implemented since 2001. The project visualizes the evaluations of over 50,000 people for 1,500 brands of companies, products, and services. It is the largest brand value evaluation survey in Japan and is useful for verifying the results of practical brand strategies, public relations activities, and marketing, as well as setting future goals. The author is also an expert in item response theory, and has been in charge of the planning, analysis, and evaluation of the Nikkei TEST since 2008, when the first public test was held.The Nikkei Test is a test organized by the Nikkei newspaper that measures the "breadth and amount of knowledge necessary for business, as well as the ability to think." The test uses questions created from real-world economics and is represented by five evaluation axes. There are four types of Nikkei Tests, which can be chosen based on the purpose and form of the test. These include a nationwide simultaneous test (online test), a corporate/group test, a test center test, and a Nikkei Test training drill. The test is a valuable tool for self-analysis and evaluation, as well as for accelerating skill development.