Weighting Overview: Standard Eurobarometer

Starting with Standard Eurobarometer 32 for each of the participating countries a comparison between the sample and a proper universe description is carried out for internal weighting purposes. For an evaluation of the post-stratification (cell) weighting in the Eurobarometer context see: Sabine Häder and Siegfried Gabler: Deviations from the Population and Optimal Weights, in: ZUMA Nachrichten Spezial. Band 2. Eurobarometer do not provide a design or transformation weight adjusting for unequal selection probability, for example as a function of household size.  

The universe description is made available by the National Research Institutes and/or by EUROSTAT. On this basis a national weighting procedure, using marginal and intercellular weighting, is applied. As such in all countries, minimum sex, age, region NUTS II (basic regions as defined by the EUROSTAT nomenclature of territorial units for statistics), and size of locality are introduced in the iteration procedure.

The population size weighting corrects for the fact that most countries have almost identical sample sizes, no matter how large or small their populations are. They ensure that each country respectively lower level sample (Northern Ireland, East and West Germany) is represented in proportion to its population size within different groupings.

Up to six Nation Weights are provided for use in separate analysis of individual countries. The following description refers to Eurobarometer 32 (Autumn 1989) and following. In the case of former Eurobarometer national weighting factors have not been provided continuously for all countries and the weighting procedure might differ from the foregoing description. For information on available weighting factors in former surveys up to Eurobarometer 31 please see corresponding weighting overview 1970-1989 and the description in the respective study documentation.

Please notice that starting with Eurobarometer 54.2 the weighting factors (as described below) are not any more adjusting the samples to their respective standard sizes! This is supposed to have no consequences for the data analysis.

Post-stratification weights

• WEIGHT RESULT FROM TARGET reproduces the real number of cases for each country. British and Northern Irish as well as East and West German samples are weighted separately. This weight is available starting with survey 34 and corresponds in principle to former NATION WEIGHT II (as available until Eurobarometer 31A). This weight can be applied when all samples are analyzed separately.
   

• WEIGHT ADJUSTED TO STANDARD SIZE is equivalent to WEIGHT RESULT FROM TARGET but adjusting all samples to the standard size of 1000 cases (respectively 300 for Northern Ireland and 500/600 for Luxembourg). For surveys 32 and 33 the 'United Kingdom' weighting factor is included. This weight is usually applied in the reports produced on behalf of the European Commission if samples are analyzed separately. This factor is only available up to survey 54.1.

Population size weights (including post-stratification)

• WEIGHT SPECIAL UNITED KINGDOM adjusts the British and the Northern Irish samples to their respective proportions in the United Kingdom and has to be applied whenever the United Kingdom is analyzed as a whole. All national weights are included. Unlike the corresponding former NATION WEIGHT I (as available until Eurobarometer 31A) all samples are adjusted to the standard size.
   

• WEIGHT SPECIAL GERMANY adjusts the East and the West German samples to their respective proportions in the united Germany. All national weights are included and all samples are adjusted to the standard size. This weight has to be applied whenever the united Germany (East+ West) is analyzed as a whole. This weight is available starting with Eurobarometer 34.
   

• WEIGHT SPECIAL UNITED KINGDOM + GERMANY combines the special weighting factors for the United Kingdom and the united Germany (East+ West) for simultaneous analysis of both. This combined weight is available starting with Eurobarometer 47.
     

• Separate weights are available for the autonomous participants Finland (before becoming official member) and Norway: WEIGHT RESULT FROM TARGET FINLAND ONLY contains weights that adjust the weighted sample to enhance the representative for Finland. The real number of cases is reproduced. WEIGHT RESULT FROM TARGET NORWAY ONLY contains weights that adjust the weighted sample to enhance the representative for Norway. The real number of cases is reproduced.
   

• The EUROPEAN WEIGHTs include the adjustments of each national sample in proportion to its share in the total population of the European Union (European Community), aged 15 and over. These post-stratification adjustments are based on population figures published by EUROSTAT in the Regional Statistics Yearbook. The EUROPEAN WEIGHTs include the national weighting factors. Up to five European weights are provided for use in analyses of the European Union population as a whole and in accordance with its historical composition. Unlike the former EUROPEAN WEIGHT (as available until Eurobarometer 31A) the total of samples is adjusted to the standard size up to survey 54.1.
   

• EURO WEIGHT 15 includes the new member countries as of the 1995 enlargement (Austria, Sweden, Finland). EURO WEIGHT 12 (also named EURO 12 - EAST GERMANY) refers to the group of twelve member countries; EURO WEIGHT 12 + adds East Germany. EURO WEIGHT 10 excludes Spain and Portugal, in addition Greece is excluded in EURO WEIGHT 9. EURO WEIGHT 6 only refers to the six EC founder members (France, Belgium, Netherlands, West Germany, Italy, and Luxembourg). WEIGHT EURO +3 refers to the group of the three new members as of 1995 (Finland, Sweden and Austria) excluding all other countries.
   

• European WEIGHT TOTAL includes Norway (if available) in addition to the 15 member countries. This weight variable is sometimes included in the original INRA data set even if Norway was not participating in the respective survey. It should only be used if Norwegian data are available and if the total population of all participating countries is to be analyzed as a whole.
   

• Starting with Eurobarometer 49 and up to survey 59.1 the additional WEIGHT SPECIAL EURO COUNTRIES separates the group of eleven countries which accepted to introduce the EURO (common currency), as of 01/01/99 (Belgium, Germany, Spain, France, Ireland, Italy, Luxembourg, the Netherlands, Austria, Portugal and Finland) from the non-EURO countries. Starting with Eurobarometer 54.0 and again up to 59.1 an additional EURO countries weight includes Greece in the group of countries which adopted the EURO as common currency, starting with Eurobarometer 67 Slovenia is included as well.   
   

• WEIGHT EURO NEW 10 refers to the group of the ten new member countries as of the 2004 enlargement. WEIGHT SPECIAL CC4 refers to the group of the four remaining accession and candidate countries, Romania and Bulgaria as accession countries with the separate WEIGHT ACCESSION COUNTRIES, Turkey and Croatia as candidates with the separate WEIGHT CANDIDATE COUNTRIES.
   

• WEIGHT EURO 25 refers to the new group of all 25 member countries after the 2004 enlargement; WEIGHT EURO 29 (EURO 25 + CC 4) in addition includes the remaining accession and candidate countries. If available, the sample for the Turkish Cypriot Community (Cyprus North) is excluded from calculation by all European weights.   

OVERSAMPLES are weighted separately as specified in the respective study documentation.