The objective of the ESS is to design, develop and run a conceptually well-anchored and methodologically bullet-proof study of changing social attitudes and values. Achieving these aims in a cross-national context requires 'optimal comparability' in the operationalisation of the study within all participating countries.

This 'principle of equality or equivalence' applies to sample selection translation of the questionnaire, and to all methods and processes. Above all, we must ensure that all procedures and outcomes are comprehensively documented in a standard way.

More detail on the sampling designs, translation strategies and development of the questionnaire is given on separate pages.