Tasks of the Sampling Unit
Fields of work
The Sampling Unit of the IEA Data Processing and Research Center plans and supports the implementation of sampling procedures and also conducts workshops on sampling, weighting, variance estimation and significance testing in large-scale assessments in education.
The following stages of the sampling procedure are planned and supported by the sampling unit:
The first phase involves development of general sampling designs. The concrete application of these designs is later based on the specific situations in the participating countries, particularly the determination of the correct sample scope or the choice of suitable stratification variables.
The next task is the preparation of the sampling procedure, such as notably the creation or verification of a selection basis for the sample. Then random samples of schools or other educational institutions are drawn from selection lists of this kind. Strict adherence to mathematical procedures in sampling ensures precise data on the exactness of study results after the study is completed.
Implementation of sampling
The implementation phase involves providing assistance to the participating countries in solving any problems that emerge as the study is being conducted. In particular, the sampling department helps in extracting samples within the chosen educational institutions, notably from classes, courses or individual students.
Weighting and evaluation of variance
A further field of activity of the sampling unit is the calculation of sampling weights and their assignment to the data sets containing the study results. Additionally, the unit also develops and implements methods of evaluating variance in studies with complex sampling design.
Olaf Zühlke/Dr. Sabine Meinck
IEA Data Processing Center
Phone: +49 40 48 500 750
Fax: +49 40 48 500 501