A theory-driven approach to evaluation (TDE) emphasizes the development and empirical testing of conceptual models to understand the processes and mechanisms through which programs achieve their intended goals. However, most reported applications of TDE are limited to large-scale experimental/quasi-experimental program evaluation designs. Very few…

The Virginia Beach City School System has utilized an experimental school year plan known as 45-15. Under this plan, schools remain in session throughout the year and students are assigned to one of four attendance cycles which begin 15 days apart. As a result of the staggered attendance pattern, only three groups (cycles) of students are in…