Ten Years of Dimensional Comparison Theory: On the Development of a Theory from Educational Psychology

Dimensional comparison theory (DCT; Möller & Marsh 2013:Psychological Review, 120(3), 544-560), first formulated 10 years ago, describes individuals' internal comparison processes applied between different areas of their lives. Dimensional comparisons explain the seemingly counterintuitive phenomenon that students' verbal and mathematical self-concepts are almost uncorrelated, even though mathematical and verbal performances correlate highly positively: When students compare their performance in verbal and mathematical domains, dimensional comparisons lead to a contrast effect: students overestimate their ability in the intra-individually better domain and underestimate their ability in their intra-individually weaker domain, leading to near-zero correlations between the respective self-concepts. This paper describes diverse extensions of the classic DCT into a variety of predictors (especially various school subjects, beyond math and native language) and criteria (especially task value components, in addition to subject-specific self-concepts) and extensions of the applicability of the DCT as an educational psychological theory to contexts such as clinical and health psychology. Recent findings on the psychological processes that trigger, accompany, and follow dimensional comparisons are summarized, before an overview of different methods to capture dimensional comparisons is given, and further research directions are discussed.