The objective of the ESS sampling strategy is the design and implementation of workable and equivalent sampling plans in all participating countries. 

Sampling in the ESS is guided by the requirements outlined in the Survey Specification and the following key principles:

  • Samples must be representative of all persons aged 15 and over (no upper age limit) resident within private households in each country, regardless of their nationality, citizenship or language
  • Individuals are selected by strict random probability methods at every stage
  • Sampling frames of individuals, households and addresses may be used
  • All countries must aim for a minimum 'effective achieved sample size' of 1,500 or 800 in countries with ESS populations of less than 2 million after discounting for design effects
  • Quota sampling is not permitted at any stage
  • Substitution of non-responding households or individuals (whether 'refusals', 'non-contacts' or 'ineligibles') is not permitted at any stage

You can find out more about the ESS sampling principles in the current ESS Sampling Guidelines.

Sampling and Weighting Expert Panel

Each National Coordination team is responsible for producing a sample design that adheres to ESS sampling principles and is suitable for implementation in their country. They are supported in this task by a member of the ESS Sampling Expert Panel who is assigned to assist them. The current members of the Panel are:

  • Peter Lynn (Chair, University of Essex, UK)
  • Piotr Jabkowski (Adam Mickiewicz University in Poznań, Poland)
  • Olena Kaminska (University of Essex, UK)
  • Mārtiņš Liberts (Bank of Latvia)
  • Blanka Szeitl (University of Eötvös Loránd, Hungary)

The work of the SWEP is supported by a statistical research officer, Carla Xena (University of Essex).

For further information on the ESS sampling principles and country-specific sampling designs, please contact the chair of the Sampling and Weighting Expert Panel Peter Lynn.

Sample Design Data Files

The sampling design has a major influence on the variance of estimators, and features such as multi-stage sampling, selection of clusters and stratification should be taken into account when producing variance estimates. Details on the sampling designs used in each ESS Round can be found in the ESS Data Documentation Report for the respective round. Information on stratification and clustering of ESS data is made available in the published Sample Design Data Files (SDDFs). The User Guide available from the sidebar documents the contents of the integrated SDDF and provides guidance on use of the data.

Integrated Sample data files by round

Related content

ESS data on this topic

  • Sample Design Data Files (SDDFs) (ESS1-ESS8)
  • From ESS9, sample design data is released as part of the integrated data file rather than in a separate file

ESS documents on this topic

Publications on this topic


Lynn, P., Häder, S., Gabler, S., & Laaksonen, S. (2007).
Methods for achieving equivalence of samples in cross-national surveys: the European Social Survey experience. Journal of Official Statistics, 23 (1), 107–124

Book chapters

Häder, S. & Lynn, P. (2007). 
How representative can a multi-nation survey be? In R. Jowell et al. (eds.), Measuring Attitudes Cross-Nationally. Lessons from the European Social Survey. London: SAGE

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For further information on the SDDFs, please contact:
Peter Lynn
Chair of the Sampling and Weighting Expert Panel