Follow-up surveys may fall prey to several sources of bias and error, among them lack of control over independent variables, lack of item validity and reliability, sampling biases, and observation bias. Two follow-up studies have been dissected to expose inherent limitations: the Texas Education Product Study (TEPS) and Project TALENT. The majority of the follow-up studies (i.e., studying graduates of a previous year) conducted fail to provide adequate information on which curriculum construction and planning can be based. Input is needed to aid in decision-making, however, and the best method readily available to provide this input is the follow-through approach (i.e., identifying a current class of students and following them beyond graduation). This approach comes closer to providing meaningful input by exercising, to some extent, a method of measuring relevant independent variables. Follow-up surveys, as they are commonly practiced, are not worth the time and effort spent conducting them. Follow-through surveys come much closer to producing information relevant to the relationships of concern to decision-makers and therefore prove much more worth the time and effort invested in using this approach. (Author/PR)