Central Data Catalog

The 17 provinces of the country were divided into four groups based on their average intra-class correlations in ASLO II (2009).

The number of grade 2 students during the school year 2010-2011 was used to estimate of the number of grade 3 students in 2012.

Ten provinces had an acceptable number of schools with more than 15 students at the targeted grade. In those provinces, schools were selected with probability proportional to size, in a single explicit stratum.

For the other seven provinces, two strata were defined: (1) all schools with at least 15 students in the targeted grade; and (2) the rest of schools. The target number of students to sample in the province was divided between the two explicit strata, proportional to each stratum's size. In the first stratum, the number of schools to be selected was equal to the number of students to be selected, divided by 15, and schools were selected with probability proportional to size. In the second stratum, the average school size was computed, and the number of schools to be selected was the total number of students to be selected, divided by the average school size.

Selection of students: If selected schools have 15 or less students at the targeted grade, all students take the assessment. If schools have more than 15 students at the targeted grade, students are randomly selected using random number tables.

Selection of teachers: Students selected to participate in the assessment were asked to identify their teacher, and whenever possible, these teachers were administered the teacher's component of the assessment. When test takers were drawn from more than one grade 3 classroom, all grade 3 teachers were assessed.


The response rates were 99.78% for schools and 93.24% for students, yielding an overall response rate of 93.03%.