Source: Pew Research Center
Even as the polling industry tries to recover from real and perceived misses in U.S. and European elections in recent years, new studies have provided reassuring news for survey practitioners about the health of polling methodology.
In this Q&A, Michael Dimock, president of Pew Research Center, talks about recent developments in public opinion polling and what lies ahead.
There’s a widespread feeling that polling failed to predict the 2016 election results. Do you agree?
President Trump’s victory certainly caught many people by surprise, and I faced more than one Hillary Clinton supporter who felt personally betrayed by polling. But the extent to which the expectation of a Clinton victory was based on flawed polling data – or incorrect interpretation of polling data – is a big part of this question.
Polling’s professional organization, the American Association for Public Opinion Research (AAPOR), spent the last several months looking at the raw data behind the pre-election polls in an attempt to answer this question. (Note: The leader of the AAPOR committee tasked with this inquiry is Pew Research Center’s director of survey research, Courtney Kennedy.) While it might surprise some people, the expert analysis found that national polling in 2016 was very accurate by historical standards. When the national polls were aggregated, or pulled together, they showed Clinton winning among likely voters by an average of 3.2 percentage points. She ended up winning the popular vote by 2.1 points – a relatively close call when looking at presidential polling historically, and significantly closer than what polls suggested in 2012.