ABSTRACT
78Richard E. Snow conceived of individuals' performances as the result of a transaction between their aptitudes and the particular characteristics of the situation in which a performance occurred over time. By aptitudes he meant the cognitive, conative, and affective resources that an individual brings to the situation. By situation he meant the characteristics of a particular environment (e.g., test) that afforded or impeded—that assisted or constrained—certain courses of goal-directed action for different individuals. In relation to achievement tests. Snow proposed that individuals' test performances emerged from the organization of their demographic background and intellectual history; an "assembly" of cognitive, conative, and affective processes needed to more or less effectively respond to a series of situation-embedded test tasks (e.g., multiple-choice items); and the ways in which the demand characteristics and opportunities of the tasks were attuned to or mismatched with individuals' aptitude resources. Performance and its determinants were not viewed as static but rather as dynamic processes unfolding over time at the interface of person and situation. From this reasoning and related empirical findings. Snow concluded that a new multivariate approach to validating interpretations of achievement test scores was needed. In this introduction to this special issue, we describe some of Snow's "big ideas" regarding issues of aptitude, person-situation transactions, and test validity. We then describe the design of the "high school study" we undertook, after Snow's passing in 1997, to explore some of these ideas further.
