Donald Trump still leads in Iowa, poll suggests

Republican presidential candidate Donald Trump answers questions from the media ahead of a campaign stop in Spencer, Iowa, Dec. 5, 2015.

Reuters/Mark Kauzlarich

Donald Trump remains in the lead in the key state of Iowa for the Republican presidential nomination, according to a new poll released by CNN.

The poll contradicts a survey released earlier in the day from Monmouth University, which showed Sen. Ted Cruz of Texas taking the lead. CNN said the discrepancy can be explained by differences in survey sampling.

The CNN poll shows Trump leading Cruz, 33 percent to 20 percent. Retired physician Ben Carson comes in third at 16 percent, while Sen. Marco Rubio of Florida wins 11 percent and former Florida Gov. Jeb Bush earns 4 percent.

By contrast, in the Monmouth poll, Cruz earned 24 percent support among likely Republican caucus goers, while Trump garnered just 19 percent.

As CNN explained, the Monmouth poll created its sample of likely Republican caucus goers by primarily interviewing registered Republicans who voted in state-level GOP primary elections in previous years. CNN, by contrast, compiled its sample of "likely" caucus goers by asking Iowa adults about their intention to participate in the caucuses, their interest in the news about the caucuses and past participation.

Among Iowa Republicans who said they've participated in nearly every caucus that they could (which is about 10 percnet of Iowa adults), Trump is in the lead with 38 percent, the CNN poll shows. White evangelicals are more hesitant to back Trump, the CNN poll shows, with the plurality (26 percent) backing Cruz.

The CNN poll was conducted November 28 through December 6.