Herman Cain, Ron Paul, Mitt Romney and Newt Gingrich are in a dead heat as the top choices for Iowans likely to attend the Jan. 3 Republican presidential caucuses.

A Bloomberg News poll shows Cain at 20 percent, Paul at 19 percent, Romney at 18 percent and Gingrich at 17 percent among the likely attendees with the caucuses that start the nominating contests seven weeks away.

Economic issues such as jobs, taxes and government spending are driving voter sentiment, rather than such social issues as abortion and gay marriage, the poll finds. Only about a quarter of likely caucus-goers say social or constitutional issues are more important to them, compared with 71 percent who say fiscal concerns.

The poll reflects the race’s fluidity, with 60 percent of respondents saying they still could be persuaded to back someone other than their top choice, and 10 percent undecided. Paul’s support is more solidified than his rivals, while Cain’s is softer. All of the major contenders have issue challenges to address.