There is a great deal of speculation but no clear answers as to the cause of the disconnect, but there is one point of agreement: Across the board, polls underestimated Trump's level of support.
Pew Research Center will call 75% cellphones for surveys in 2016
We’re making this change to ensure our survey samples properly represent the now roughly half (47%) of U.S. adults who only have a cellphone.
Advances in Telephone Survey Sampling
Telephone surveys face numerous challenges, but some positive developments have emerged, principally with respect to sampling.
Coverage Error in Internet Surveys
With 89% of U.S. adults online, survey research is rapidly moving to the Web. But 89% is not 100%, and surveys that include only those who use the internet run the risk of producing biased results.
What we learned about surveying with mobile apps
No research has compared app-based surveys with polls administered via Web browsers. Our new, experimental work compares the results of these two modes.
Pew Research will call more cellphones in 2015
An estimated 46.5% of U.S. adults are cell-only today. To keep pace with this trend, the Pew Research Center will increase the percentage of respondents interviewed on cellphones in its typical national telephone surveys to 65%.
Pew Research increases share of interviews conducted by cellphone
In the coming months, 60% of interviews in our national polls will be conducted via cellphones and 40% on landline phones.
About Pew Research Center Pew Research Center is a nonpartisan fact tank that informs the public about the issues, attitudes and trends shaping the world. It conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research Center does not take policy positions. It is a subsidiary of The Pew Charitable Trusts.