Why is Alaska Polling So Bad?

Sam Wang notes that “in any given year, approximately 10% of Alaska’s population has just arrived or is about to move away.”

“This is reminiscent of Nevada, which has very similar statistics. Nevada is also the site of a spectacularly wrong polling error. In fall of 2010, surveys unanimously showed Republican Sharron Angle favored to unseat Democratic Senator (and Majority Leader) Harry Reid, by a median of four percentage points. Every data-based prognosticator, including me, expected Angle to win. Yet Reid won the election by 5 points, outperforming polls by 9 points. I regard this as the worst miss of Senate polling in the last three election cycles.”

“Based on the extreme mobility of Alaska residents, I suggest a problem of potentially far larger impact. Like Nevada, telephone-based surveys in both states simply fail to capture a sample that is fully representative of voters. In other words, I suggest that ideologically diverse states with lots of recent arrivals are subject to inaccuracy.”