NYT:

Pre-election polls in numerous countries this year have widely missed their marks, often by underestimating support for candidates on the ideological fringes. The polling failures in countries like Britain, Poland and Israel point to technical issues that could well foreshadow polling problems in the United States, many analysts believe.

“The industry has a collective failure problem,” said John Curtice, the president of the British Polling Council and a professor of politics at the University of Strathclyde in Glasgow. Partly this is the result of changing methodologies. “It’s now a mix of random-digit dialing — that is, telephone polls — and Internet-based polls based on recruited panels,” he said. Both modes present potential problems.