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…

Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

This study analyzes nationally-representative quantitative data from the first (2002) and second (2004) waves of the Educational Longitudinal Study to examine the relationship between Latina/o secondary school students' degree of English-language proficiency (ELP), mathematics course-taking measures, and 12th grade mathematics achievement.…