ECS 2013 - Sampling
The sample used in the 3rd ECS aims at a full representation of businesses and other organisations with 10 or more employees in each country covered by the survey. In each country, a multi-stage, stratified random sampling design was used. The sampling approach takes into account the challenges in terms of the coverage criteria and in providing a coherent approach across the countries.
Individual sampling plans were created for each country. In each country the sampling frame was selected to provide the optimal balance between the unit of the entries (which ideally is the establishment), the effective coverage rate and the frequency of updating. Samples were drawn on the national level explicitly stratifying by establishment size (10-49, 50-249 or 250+ employees) and by broad industry sector (production industries, service industries, public services). Due to the absence of information in many countries on the exact allocation of organisations to the public services, 10% of the originally assigned sample was allocated to the public services (NACE Rev 2 categories O, P and Q).
In countries where the optimal quality frame was a company-level frame, stratified multi-stage random sampling without replacement was applied, in which the companies were the Primary Sampling Units (PSUs). The establishments were the Ultimate Sampling Units (USUs) and the final stage of the sampling (establishment selection) was carried out in a screener interview. Stratified simple random sampling without replacement of establishments was adopted in countries for which the optimal quality sampling frame was at the establishment level.
The target sample size for the management interviews ranged from 300 in the smallest countries to 1650 to the largest countries, reflecting the population of establishments with 10+ employees in the different countries. The total achieved sample was 30,113 management interviews, out of which it
A breakdown of the achieved and target sample sizes by country is available.
The final stage in sampling activity was to identify suitable respondents for the management interview and the employee representative interview.
Respondents for the management interview – the most senior persons at the establishment in charge of personnel - were identified during the screening phase.
Respondents for the employee representative interview were identified in the interview with the management respondent. The designated respondent was a chairman, secretary or spokesperson of the preferred employee representation body. To match the selection procedure with the specificities of structure of official employee representation in each of the countries, Eurofound asked its network of European correspondents to provide information on official structures of employee representation at the establishment level in their countries. Based on this information the sections on the presence of employee representation and selection of the suitable respondent in the management questionnaire were drafted to meet the country specificities and an order of preference for the selecting of a respondent whenever more than one structure was present was set up.
For more information please see the Sampling report