WASHINGTON, D.C. -- Barack Obama's release of his long-form birth certificate in late April appears to have removed some -- but not all -- doubt among Americans about where the president was born. More Americans now say he was definitely born in the United States (47%) than did so before its release (38%) and they are joined by 18% who say this is probably the case. Significantly fewer -- but still 13% -- say he was probably or definitely born in another country.
The most recent results are from a Gallup poll conducted May 5-8, while the prior results are from an April 20-23 Gallup poll. Obama released his long-form birth certificate on April 27.
The release came after years of skeptical chatter on the topic and vocal criticism of Obama from some Republicans, including Donald Trump, for withholding the document. While it may not yet be clear whether the most vocal so-called "birthers" were convinced by the certificate's release, the Gallup surveys show that many Americans across the political spectrum were.
Nearly half of Republicans (49%) now say Obama was definitely or probably born in the U.S., up from 35%. The same is true for 65% of independents, up from 56%, and 81% of Democrats, up from 78%. Republicans are 20 percentage points less likely to say Obama was definitely or probably born in another country, though 23% remain steadfast in this view. They are joined by 14% of independents and 5% of Democrats.
President Obama's release of his long-form birth certificate appears to have significantly reduced skepticism about his place of birth, but by no means completely. All political groups are more likely after the release than they were before it to say Obama was definitely or probably born in the U.S. Still, 13% of all Americans and nearly one in four Republicans continue to say he was definitely or probably born in another country. And one in five Americans still say they don't know enough to say one way or the other.
Results for this Gallup poll are based on telephone interviews conducted May 5-8, 2011, with a random sample of 1,018 adults, aged 18 and older, living in the continental U.S., selected using random-digit-dial sampling.
For results based on the total sample of national adults one can say with 95% confidence that the maximum margin of sampling error is ±4 percentage points.
Interviews are conducted with respondents on landline telephones and cellular phones, with interviews conducted in Spanish for respondents who are primarily Spanish-speaking. Each sample includes a minimum quota of 400 cell phone respondents and 600 landline respondents per 1,000 national adults, with additional minimum quotas among landline respondents for gender within region. Landline telephone numbers are chosen at random among listed telephone numbers. Cell phone numbers are selected using random-digit-dial methods. Landline respondents are chosen at random within each household on the basis of which member had the most recent birthday.
Samples are weighted by gender, age, race, Hispanic ethnicity, education, region, adults in the household, and phone status (cell phone only/landline only/both, cell phone mostly, and having an unlisted landline number). Demographic weighting targets are based on the March 2010 Current Population Survey figures for the aged 18 and older non-institutionalized population living in U.S. telephone households. All reported margins of sampling error include the computed design effects for weighting and sample design.
In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.
For more details on Gallup's polling methodology, visit www.gallup.com.