An Introduction to Factor Analysis
The discussion in Chapter 1 clarified that psychometric (test) theory is concerned with latent constructs and their evaluation. A statistical methodology with a rich history, which deals with indirectly observable variables like latent constructs, is factor analysis (FA). This methodology can be considered in some sense the backbone of the present book. In this chapter, we introduce the basics of factor analysis. Our treatment is purposely at an introductory level, because we use FA more as a means throughout this book rather than as an end in itself. For more extensive and detailed discussions of FA, we refer readers to McDonald (1985), Johnson and Wichern (2002), and Cudeck and MacCallum (2007). Later chapters in the text deal with various additional applications of FA that address specific psychometric-theory-related concerns.