Pew Research Center Spring 2014 Survey
The survey in Brazil was conducted under the direction of Princeton Survey Research Associates International.
Results for the survey in Brazil are based on 1,003 face-to-face interviews with adults 18 and older, between April 10 and April 30, 2014. Interviews were conducted in Portuguese. The survey is representative of the country’s adult population. The survey is based on a multi-stage, area-probability design, which entailed proportional allocation of interviews by region and size of municipality. The primary sampling units were municipalities.
The margin of sampling error is ±3.8 percentage points. For the results based on the full sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus the margin of error. 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.