This chapter focuses on what has become known as the psychometric or nonrepresentational approach to measurement. It considers the issues traditionally discussed under the heading of reliability, and reviews several still persistent definitions or types of reliability coefficients. The chapter discusses the problems and misuses of coefficient alpha, the most commonly used psychometric index in social-personality psychology. It suggests the generalizability theory as a broader and more heuristic perspective. The chapter examines issues related to construct validation. It also considers the construct validation as the crucial issue in psychological measurement and includes a broad range of validity evidence, focusing on convergent and discriminant aspects. The chapter describes model testing in construct validation and scale construction. It also focuses on the measurement models in structural equation modeling. The chapter reviews three classical strategies (external criterion, rational-intuitive, and internal-factor analytic) and also suggests an integrated model adopting the construct-oriented approach.

This chapter discusses a core problem that has plagued the study of intelligence for decades, the complexity of behavior. The central tenets of dynamic systems, which underpin efforts to analyze the organization and development of behavior in its complexity are outlined, keeping person and context connected and treating variability as the starting point for analysis. The classic approaches to intelligence, psychometric, Piagetian, nativist, and dynamic/constructivist are reviewed. The chapter explains how disputes between them have illuminated learning sequences, resolved important questions, and paved the way for a dynamic approach to intelligence are shown. The dynamic skill theory framework, emphasizing its conceptual origins in dynamic systems, ways that it has advanced understanding variability and consistency in intelligence, and its relevance to understanding childhood intelligence are introduced. The areas where dynamic systems concepts and models have generated usable knowledge directly relevant to intelligence, learning, and the practice of education are considered.