10/25/15, "CBS News 2016 Battleground Tracker, Iowa," YouGov
"Sample 529 Likely Republican Caucus Voters, conducted October 15-22, 2015, Margin of Error ±6.5%
CBS News YouGov poll Methodology:
Online interviews of registered voters, some contacted by phone:
"The CBS News 2016 Battleground Tracker is a panel study based on interviews conducted on the internet of registered voters in Iowa, New Hampshire, and South Carolina. The poll was conducted by YouGov, an online polling organization.
The ﬁrst wave was ﬁelded between September 3-10, 2015, with 4860 respondents, and the second wave ﬁeldwork was completed between October 15-22, 2015, with 3952 respondents, the majority of which are recontacts. Respondents were selected from YouGovs and two other online panels. These are “opt-in” panels which are open for anyone to join. However, YouGov also randomly selected persons from voter registration lists who had previously voted in primary elections and contacted them by phone. A total of 20017 registered voters were contacted by phone and the YouGov sample includes 1290 phone recruits."
Added: 32% of Iowa Trump supporters say
they won’t change their mind. Only 15% of Carson supporters say they won't change their mind:
Poll dates, Oct. 16-19. Margin of error 4.9, 401 R caucus goers
10/23/15, "Bloomberg Politics Des Moines Register Iowa Poll," by Selzer and Co.
10/23/15, "Iowa Poll: Carson surges to 9-point lead; Trump slides," Des Moines Register, Jennifer Jacobs
"Only 15 percent of his (Carson's) backers say their
mind is definitely made up. For Trump, a more substantial 32 percent say
they won’t change their mind about him....
22 percent of (Iowa) Republican likely caucusgoers say their minds
are made up; 78 percent say they could still be persuaded to support
another candidate as their first choice."...