Out of 210 primary schools, 140 were randomly assigned to receive the Extra Teacher Program (ETP). The remaining 70 schools served as a comparison group.
In 2005, the first year of the program, the ETP contract teacher was assigned to grade 1. Two sections were created for grade 1, one taught by regular civil service teachers (with multiple teachers rotating in an out of the class, teaching different subjects) and one taught exclusively by the contract teacher. As a result, average class size in grade 1 was only 44 in ETP schools, compared to 82 in comparison schools. In the second year of the program, the ETP teacher moved to grade 2, such that the cohort of first graders that benefitted from the ETP program continued to benefit once in grade 2.
While in half of the ETP schools (the "non-tracking ETP schools"), students were divided into sections at random, in the other half (the "tracking ETP schools"), students were divided into sections based on students' level of preparedness (as measured by exam scores during the first term). For all schools, which section was taught by the ETP contract teacher was then decided by random draw.
Finally, half of the schools assigned to ETP, including both tracking and non-tracking schools, were randomly selected to receive School-Based Management (SBM) training.
Standardized tests covering math and literacy questions were administered to each school just before the program ended and again one year later. Five unannounced visits were also made to each school to measure teacher effort and to observe the classroom environment.