Sampling
The PILNA sampling framework
PILNA uses a sampling design that accommodates regional complexities.
These include the differences in small to large education systems, geographically distributed and hard-to-access schools, and hundreds of spoken languages and dialects.
It draws on best practice sampling designs from other international large-scale surveys, such as the Programme for international student assessment and Trends in international mathematics and science study.
The PILNA sampling framework is designed to obtain accurate estimates of student performance across the participating countries. It has the following objectives:
- to support the accurate assessment and monitoring of learning outcomes of Pacific Island children using world-class materials and good quality, standardised procedures;
- to enable comparisons across similarly defined populations from other parts of the region, as well as to make comparisons over time; and
- to support the development of a body of expertise and experience in conducting high quality survey work that can inform other national initiatives.
To meet these objectives, certain standards, such as sample size and the extent of sampling exclusions, are agreed upon between EQAP and participating countries before the administration.
PILNA has two populations in the Pacific that it draws samples from: year four students and year six students. The definitions for these populations are given below.
Year four student population
Counting from the first year of International Standard Classification of Education (ISCED) level one, year four students are those who have completed approximately four years of formal schooling.
For most Pacific countries, the target year is year four (towards the end of the fourth grade of schooling). For Northern Pacific countries, which have a different school year, the target year is grade five (at the beginning of the fifth grade of schooling). In Papua New Guinea, the target year is grade three (towards the end of four years of formal schooling).
Year six student population
Counting from the first year of ISCED level one, year six students are those who have completed approximately six years of formal schooling.
For most Pacific countries, the target year is year six (towards the end of the sixth year of schooling). For Northern Pacific countries, the target year is grade seven (at the beginning of the seventh grade of schooling). In Papua New Guinea, the equivalent target year is grade five (towards the end of six years of formal schooling).
Sampling design
These populations are accessed through schools in the region. PILNA is administered in schools that are asked to participate, based on certain criteria.
The expected response rate for PILNA is more than 85% of sampled schools. If the response rate is below 85%, a pre-determined, systematic use of substitute schools is implemented.
Each school that is initially selected for participation has two substitute schools assigned to it. The exception to this is countries with very few schools.
Schools may be excluded from the sampling, mainly for practical reasons, such as increased survey costs or difficult survey conditions. Examples of school-level exclusions are:
- schools in very remote locations;
- very small schools; and
- international schools (offering a curriculum other than the prescribed national curriculum).
A detailed discussion of the sampling design for PILNA 2021 is presented in the PILNA 2021 Technical Report.
