Sampling
Gergely Hideg at Gallup Europe is the Team Leader for the area of Sampling. Gallup has extensive expertise in the delivery of surveys and in sampling procedures.
For the European Survey on Language Competences, it would be prohibitively expensive and too demanding logistically to survey all of the students of the appropriate age learning English, French, German, Italian and Spanish across Europe. Therefore a representative group of students learning the two most frequently taught of these languages within a country will be tested.
Rigorous sampling procedures are vital for the survey so that the data collected is comparable across each of the participating countries. The sampling process consists broadly of two main stages. First, selecting a sample of schools within each country and second, selecting a sample of students from the schools sampled.
In order to select the sample of schools, a full list of all schools that are eligible (i.e. those where English, French, German, Italian or Spanish is taught at the applicable grade and for a minimum of one academic year) is needed for each country participating in the survey. For each country, a minimum of 71 schools for each of the two languages tested will be selected in each of the participating countries. For the Field Trial this number will be reduced to 40 schools per language.
Countries are also able to select stratification variables. This means, for example, if a country wants to specifically look at the performance of public compared to private schools or the performance of schools across regions, they are able to do this. Weighting will be applied to ensure that the selection of schools remains representative of the whole country.
The second-stage following the selection of schools is to sample students. From the list of sampled schools, a list of eligible students from each school will be drawn up. From this an average of 25 students per school will be sampled.
The SurveyLang sampling team has designed a custom web-based sampling portal which allows two-way communication between National Research Coordinators, and their sampling experts, and SurveyLang on sampling related tasks.