The value-added approach to the assessment of student outcomes examines actual or inferred changes in students' performance over time. It also attempts to separate the net effects of instruction from previous ability or simple maturation. Others may have different definitions of this concept, and this vagueness causes problems. Suggested ways to improve value-added assessment include the cross-sectional research design; methods of estimating the effect of a particular collegiate experience independent of students' pre-college differences; multiple regression analysis; analysis of joint or redundant effects not directly attributable to instruction; and the development of causal models. It is also noted that value-added assessments which consider only the general effects of college disregard the possibility that not all students may benefit equally from the same experience. Further attention to this area of research is needed. (GDC)