The book provides examples of state-of-the-art analytical techniques for pursuing fundamental research problems, and the latest advances in measurement methods, with a focus on validity improvement. Eminent researchers discuss and provide insights into questions such as: Is it possible to train individuals to think at a higher level than normal for their age? What determines prospective preschool teachers' skill to perceive mathematics-related preschool situations? Can international indicator design and instruments be improved to use trends and national context variables more efficiently? Can indicator data at national, school and class levels be compared easier? Are value-added measures of teacher effectiveness valid when it comes to hiring and promoting teachers? Is money better spenton teacher training than on smaller class-size? How do theory and empirical statistical data intertwine in building structures of understanding?

This book is inspired by the career and personal influence of the Swedish scholar Professor Jan-Eric Gustafsson, renowned for his research on individual differences, especially the structure of cognitive abilities, and on the effects of education on knowledge and skills.