The fourth cohort of the Teacher Incentive Fund federal grant competition ("TIF4") included special consideration for projects that would identify, develop, and utilize master teachers as leaders of STEM education. In September 2012, the Houston Independent School District (HISD) was awarded a TIF4 grant for $15.9 million to implement a human capital approach to improving STEM education. The TIF4 project schools were among the HISD schools serving grades K-8 with the highest student economic disadvantage and the most risk factors for chronic absenteeism. A human capital approach to strengthening STEM education addressed the TIF4 project schools' need for high-quality supports for student learning, and the systemic challenges to teacher retention, development, and recruitment in hard-to-staff subjects. This report overviews the performance-based compensation strategies implemented through the TIF4 grant, and situates the TIF4 schools in the context of HISD's historic challenges for new teacher retention, effective teacher retention, and the retention of math and science teachers. [For the first two reports in this series, see ED603678 and ED603680.]