Friday, January 18, 2008

South Carolina Republican Endgame

South Carolina is looking quite interesting for the Republicans. There has been a decent amount of polling since Iowa, with Huckabee getting a brief bounce but subsequently subsiding a bit, while McCain has gained since the first of the year. There is little evidence that Romney benefited significantly from his Michigan win. Fred Thompson has risen a bit, based on the sensitive estimator, but still trails in fourth place.

If we try to pick these data apart a bit, the sensitive red estimator is trying hard to fit Huckabee's varying fortunes. His December rise, and Iowa bump are picked up, but if those were real then so is the decline we see to his current level of about 22%. Whether he has been trending up down, or flat depends on how wide your view of the polling is. The blue estimator has the longest run view, and still see's him improving over his showing in 2007, but that was ages ago politically. The sensitive red estimator is showing a downturn since Iowa, but if you squint hard and ignore the earliest post Iowa polls you might believe you can still see some rise in the last week or 10 days. But do note the bottom line: the two different trend estimates still put his current support at between 21.6% and 23.3%. So while they disagree on immediate trends, the end up close to the same bottom line.

For McCain, there is little dispute that he has surged since early December when he was in the low-teens to somewhere in the mid-to-upper 20s today. The sensitive estimator thinks the rate of climb since Iowa has been more rapid that does the blue estimator, but again both put his support between 26.9% and 29.3%.

One big question in South Carolina is whether conservative criticism of both Huckabee and McCain is having any effect. If Thompson is benefiting from that, his polls only modestly show it. The sensitive estimate suggests a rise from about 10% to about 14%, but there is no polling evidence for a surge that would allow him to compete for first place.

Finally, Romney's Michigan win seemed to help him in Nevada (based only on 3 polls, I should add) but there is no evidence of a bounce in South Carolina. After spending Wednesday and part of Thursday in the state, Romney appeared to concede the race and moved on the Nevada to campaign, where his chances look better. The Romney trends are also in complete agreement: No substantial trend, and both agree on 16%.

One big warning here. South Carolina has shown suprising numbers of undecided. The Fox poll today, for example, has an unbelievable 19% undecided. That is HUGE. And, if you add up the trend estimates for the four top candidates here, you get... 81% leaving the same 19% unallocated. In Fox's poll, less than 10% pick Paul, Giuliani or Hunter combined, so there is a gigantic amount of room for those last minute deciders to break one way or the other.

With a history of under-the-radar negative campaigning in the state, and evidence of the same this year, it would be surprising if we don't see some important shifts here at the end.

In New Hampshire and Michigan, those late shifts have benefited the first place finisher disproportionately.

This chart is an attempt to illustrate the variation in the polling over the past week. (A comment raised some good questions about it, so let me try to explain it better.) The horizontal axis is the current sensitive trend estimate for each of the top four candidates. The vertical axis is the actual poll results since the Michigan primary. The point is that the sensitive trend puts the order as McCain, Huckabee, Romney and Thompson. But the vertical spread of the points for each candidate shows how much variation we've see from poll to poll. While most of the McCain polls are higher than most of the Huckabee polls, there is some overlap. Likewise most of Huckabee's results are higher than Romney. But Romney and Thompson show considerable overlap. The less the overlap, the more reasonable it is to believe the separation between candidate trends is reliable, and the more overlap the greater the uncertainty. If all the polls showed exactly what the trend estimate shows, then the points would all be on the diagonal line, and there would be no disagreement at all. The fact that most of McCain's polls are below the 45 degree line shows that he has been trending up, while Huckabee's points are mostly above the diagonal, consistent with his recent downward trend. Romney and Thompson are about equally above and below the diagonal, showing little trend over the last eight polls since Michigan.

But the simple point is that the more spread you see vertically, the more uncertainty. And the more overlap between pairs of candidates, the more uncertainty.

For me, that 19% undecided in the Fox poll is scary. And fun!