Catalogue de données central

The sample is drawn using a proportional stratified random sampling strategy. The country is divided into 16 strata based on geographical location, school location and school type. In the first stage, 25 districts out of 75 are randomly selected. In the second stage, schools are randomly sampled in the selected districts, the number of sampled schools being proportional to the number of schools in each stratum. Students in all grade 3 and grade 5 classrooms are selected using simple random sampling.