Survey respondents probed after an initial "don't know/refused" response give systematically different answers than those not probed for a response.
Text messaging is widely used in the U.S., but it appears to have significant drawbacks as a primary way to reach survey respondents.
Hear directly from Gallup's methodologists about our latest experiments and recommendations for conducting public opinion research.
Find out which of President-elect Trump's proposals are in sync with American public opinion, which are not and which fall in the middle.
Hillary Clinton's margin over Donald Trump in the national popular vote will be close to two percentage points, making the 3.3-point Clinton margin in the pre-election national poll average remarkably accurate.
The controversy over the state-based religious freedom laws in Indiana and Arkansas highlights the continuing impact of religion on social and policy issues in this country.
The visit of Israeli Prime Minister Benjamin Netanyahu to the U.S. and his speech before Congress on Tuesday has underscored, if not exacerbated, the abundant political differences in elected officials' views of the prime minister and of Israel and the Middle East situation more generally.