Over the next week, we’re going to see a lot of polling in South Carolina, and note the consistencies and the differences between them, and Ramussen and ARG get us off to a good start today.  Both polls released today show Mitt Romney in the lead, and both show Newt Gingrich in second place — but the two diverge at that point:

Mitt Romney leads the South Carolina Republican presidential primary with 29%. Newt Gingrich is in second place with 25% and Ron Paul is in third place with 20%.

Paul has gained the most and Rick Santorum has lost the most since the last American Research Group survey on January 4-5. In that survey, Paul was at 9% and Santorum was at 24%.

Gingrich and Romney are tied among self-identified Republicans with 29% each, followed by Paul with 18%. Paul leads among independents and Democrats with 29%, followed by Romney with 27%, Gingrich with 12%, and Rick Perry with 11%.

Gingrich is a little closer to Romney in this poll, within four (and the margin of error) rather than seven in Rasmussen.  Paul’s position in this poll isn’t far off from what Rasmussen showed, 16% and a tie for third place.  For Santorum, though, the difference between the two is profound.  He’s lost ground in South Carolina in both polls, but in Rasmussen it’s eight points, and in ARG it’s seventeen, down from 24% in last week’s ARG survey.  That seems strange for a candidate who hasn’t made a gaffe that would be worthy of such a one-week swing in polling support, and it makes me question whether ARG’s sampling was off this week or last week.

The methodology for both looks solid, though.  Rasmussen has a sample of 750 likely voters taken in a single day; ARG uses 600 likely voters surveyed over two days, somewhat smaller but still more than large enough for a state-wide poll.  ARG has significantly fewer non-Republicans at 79/21 to Rasmussen’s 71/29, but that should hurt Paul rather than help him.  We could value the two surveys based on their predictive accuracy in New Hampshire, but as it turns out, they were almost identical.

Both polls give the basic outline of the race in South Carolina, which is that Romney leads by a small but significant amount, and Gingrich is closest to him at the moment.  Both pollsters and many others will undoubtedly weigh in again on this state, and we will see whether either or both of these turn out to have the pulse of the electorate or end up being outliers.