The Innovative STEM--Computer Science and Engineering Design (STEM CSED) project (Award #: U411C190169), funded by an Early-Phase Education Innovation and Research (EIR) grant, sought to strengthen math achievement and foster positive attitudes toward STEM and computer science among students in Waukegan Community Unit School District #60, a large, high-needs district in northern Illinois. The intervention combined three components: (a) 18 credit hours of collegiate coursework in STEM/Computer Science, (b) monthly professional development focused on STEM pedagogy, and (c) implementation support for a district-developed STEM CSED curriculum with classroom resources. A quasi-experimental design with 20 schools (10 treatment, 10 comparison) employed a Comparative Interrupted Time Series (CITS) analysis of NWEA MAP math data and student attitudinal surveys. More than 9,500 students participated between 2021-2024. Results indicated that while both groups experienced COVID-related declines, treatment schools significantly outperformed comparison schools in math achievement following program implementation. Effect sizes ranged from d = 0.21 after one year to d = 0.34 after two years, reflecting small to moderate positive impacts. No statistically significant differences were observed in student attitudes toward STEM, though treatment schools showed less decline in attitudes toward computer programming during partial implementation. [This report was prepared by Education Potential LLC and submitted to Waukegan Community Unit School District #60.]