| Due to the variety of factors that may affect student achievement, individual students often come to schools with different levels of academic preparation. These students from diverse academic background come with different learning needs. So, to better serve them, schools have adopted a variety of strategies, including increasing instructional time, reducing class sizes, providing differentiated curriculum and improving teacher quality through professional development trainings. My dissertation consists of three papers that examine several education interventions targeting at students with different academic abilities. These studies examine the design and current uses of several popular education interventions, and provide actionable insights on improving these interventions to enhance learning experiences for students at different points of the achievement spectrum.;Chapter one evaluates a multi-subject remedial program that provided additional instruction on math and reading to under-performing students in a large metropolitan school district. Using a fuzzy regression discontinuity design and school administrative records, I find that double-dose remedial math courses improve math test scores by 0.21 standard deviations at the end of the school year. Yet, the effect of double-dose reading courses on reading achievement is small and statistically insignificant. In addition, the required extra classes in math or reading do not have crowd-out impact on instruction time and student performances on non-targeted core subjects. Finally, the study shows that students who receive treatments in multiple subjects do not necessarily have larger gains. While double-dose math courses may improve students' math skills, the effect disappears for students who were taking double-dose reading courses at the same time. This finding suggests that two separate double-dose courses in different subjects may be ineffective in improving student achievements. To support students who struggle with more than one subject, schools should consider redesigning the double-dose courses with alternative curriculum and instructional strategies to integrate content of different courses and to increase student engagement.;Chapter two examines effects of taking accelerated math courses under a subject-based acceleration program for middle school students. Students assigned to accelerated courses were exposed to more advanced curriculum and higher-performing peers. Using school administrative records and fuzzy regression discontinuity approach, the study finds null effects of taking accelerated math courses on students' end-of-grade math test scores. Specifically, the effects are insignificant for students who took accelerated courses in both math and English Language Arts, and for those who took accelerated courses only in math. Also, the effects are insignificant for low-income and minority students. These findings are unexpected given the treatments provided by accelerated courses. The study provides possible explanations to the findings, and suggests directions for future research.;Chapter three examines the sustainability of teacher knowledge gains from teacher professional development (PD) programs. Teacher PD is seen as a promising intervention to improve teacher knowledge, instructional practice, and ultimately student learning. While research finds many instances of significant program effects on teacher knowledge, little is known about how long these effects last. If teachers forget what is learned from the professional development program, the contribution of the intervention will be diminished. Using a large-scale dataset with 3,340 in-service teachers from 161 programs, this study examines the sustainability of gains in teachers' content knowledge for teaching mathematics (CKT-M). Results show that there is a negative rate of change in CKT after teachers complete the training and that this estimated rate is relatively stable over time, suggesting that the average gain in test scores before and after the program is lost in just 37 days. There is, however, variation in how quickly knowledge is lost, with teachers participating in summer programs losing more rapidly than those who attend programs that occur during school years. The implications of these findings for designing and evaluating professional development programs are discussed. |
