This study is the first statewide analysis of the effectiveness of the Texas Teacher Incentive Allotment (TIA) program. Introduced in 2019, TIA is the most significant and unprecedented teacher merit-pay system in the U.S. Leveraging the Synthetic Control Method (SCM), we construct a counterfactual scenario to assess the causal impact of TIA on the initial 26 participating districts, focusing on teacher turnover rates and standardized assessment scores in math and reading. Using statewide data from 2014-15 to the 2022-23 school years, we show TIA had a large, positive impact on teacher retention and student achievement. Our findings contribute insights into the debate on merit-based compensation and underscore how large-scale teacher compensation strategies may combat long-standing shortages and improve student outcomes.