Our surveys internationally are conducted via telephone or face-to-face interviews, depending on the country. Face-to-face interviews are either computer-assisted personal interviews (CAPI) or pen and paper interviews (PAPI). The results are based on national samples, unless otherwise noted. Included here is detailed information, such as mode of interview, sampling design, margin of error, and design effect, for each country we survey, organized by survey, country and year.
For more general information on how we conduct our international survey research, visit here.
The margin of sampling error reported is based on all interviews conducted in a country. The margin of error takes into account the design effect due to clustering and weighting, where applicable. For results based on the full sample in a given country, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus the margin of error. The margin of error is larger for results based on subsamples in the survey. Sample sizes and sampling errors for subgroups are available upon request. In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.