Central Data Catalog

The sample is drawn using a two-stage stratified cluster sample design. Location, type of school, and school language of instruction are used as stratification variables. In the first stage, schools are sampled from each stratum using probability proportional to size. In the second stage, classrooms are selected using simple random sampling. All students in sampled classrooms are assessed.


The schools weighted participation rate is 94.5%.
The students weighted particiaption rate is 84.6%.