Prior research into computer-assisted instruction (CAI) has demonstrated that the use of technology in the classroom has the potential to help underperforming young learners. The literature has also stressed that thorough evidence-based testing is needed to ensure that effective instruction is provided to students and that accurate information is available to educators. This study explored the effect of an adaptive CAI program on learning outcomes for young students. Kindergarten and first grade students used the Waterford Early Learning Program (WEL), a computer-adaptive reading curriculum, and were assessed at the beginning and end of the 2016-2017 school year. Analysis of gains found that students in both grades who used WEL benefited from significantly greater growth in literacy skills than a historic dataset of students from the previous year who did not use WEL. Students who used WEL outperformed their control counterparts on end of year scores despite having lower beginning of year scores on most strands. In this study, WEL improved the literacy scores of the students who used it, indicating that computer-assisted instruction can make a positive impact on students' early literacy skills.