This case study describes the use of a regression discontinuity design and a quasi-experimental design to evaluate the impact of School Improvement Grants on high school students’ reading, mathematics, and science achievement. The high schools that participated in the School Improvement Grant program were very low performing and received approximately US$1 million a year to help turnaround their academic performance. The schools’ scores on their applications for School Improvement Grant funding were used as the assignment variable in the regression discontinuity design. We conducted a number of sensitivity analyses to determine whether the estimates of program impact varied across the two research designs. The study is a demonstration of the use of regression discontinuity design in a real-world setting and showed that researchers can have more confidence in their findings when the results from multiple designs are consistent with one another. Overall, the results do not indicate that the School Improvement Grant program positively impacted the high school students’ reading, mathematics, and science achievement during the program’s first 2 years.