Large efforts were taken to guarantee high scientific quality standards of the survey. First, all existing questions were critically reviewed by a Theory Group which also proposed new questions and items to be added to the questionnaire. This group also made sure that all questions were standardized between waves and between countries. A serious improvement is the rich set of socio-demographic background variables which was added to the questionnaire, facilitating far-reaching analyses of the determinants of values.
The Council of National Program Directors critically reviewed this process and approved the final master questionnaire. In addition, the translation process, fieldwork procedures, and data processing were standardized according to strict guidelines developed by a Methodology Group.
In all countries, a representative multi-stage or stratified random sample of the adult population of the country 18 years and older, was approached for face-to-face interviews. Interviewers were thoroughly trained before they went into the field and made at least three revisits in case of not reaching the selected respondent at the first visit. Interviewers completed a predefined contact form for each visit and quality control back-checks were made.
The National Program Directors were responsible for the fieldwork in their country. Coordination of the fieldwork was done by EVS teams at Tilburg University, CEPS/Instead, and GESIS. The Executive Committee ‘steered’ the whole project, under the supervision of the Board of the EVS Foundation.
For more information on standardized translation process, fieldwork procedure, and data processing go to High-Quality Fieldwork.

Access to data and documentation

Data and Documentation– more information about the standards and recommendations of EVS 2008, fieldwork procedures in the countries, and outcomes provided in method and variable reports.
Participating countries and country information – comprehensive documentation of national datasets on study and variable level are provided in PDF format.

Comparisons across EVS waves

The Common EVS/WVS Dictionary – EVS Trend provides an overview of all variables used in the five EVS waves and their correspondence in terms of comparability. Further, the EVS variable catalogue in the GESIS Search contains the variable documentation and enables the search for variables and questions as well as their comparison.
EVS 1981-2017 Method Overview provides summarized information for all participating countries on origin and content of data in the single EVS waves.