Discipline-based education researchers have a natural laboratory--classrooms, programs, colleges, and universities. Studies that administer treatments to multiple sections, in multiple years, or at multiple institutions are particularly compelling for two reasons: first, the sample sizes increase, and second, the implementation of the treatments…

Data from 787 international undergraduate students at an urban university in the United States were used to demonstrate the importance of separating a sample into meaningful subgroups in order to demonstrate the ability of an English language assessment to predict the first-year grade point average (GPA). For example, when all students were pooled…

Author cocitation analysis was used to investigate changes in intellectual structure of macroeconomics over two consecutive time periods, 1972-1977 and 1978-1983. Profile analysis, nonmetric multidimensional scaling, and clustering techniques were used to create two-dimensional maps displaying changing relationships among 41 authors as perceived…