Sabato contends that “the truly remarkable thing is that polling is as accurate as it is.” But he fully admits their predictive limits:
First, we can probably expect up to a baker’s dozen of Senate contests to remain highly competitive right up to Election Day. Second, polling averages are likely to mislead us about the eventual winner in one or two cases. And finally, if there should be multiple Senate contests where the pre-election polling average has the candidates separated by three percentage points or less, the polling leader in about a third of these cases may well lose.
Therefore, if we’re headed for an election that produces a Senate divided by only a seat or two, don’t expect polls to precisely predict the outcome. Even well-conducted, large-sample surveys are blunt instruments with a margin of error.
Enten keeps an eye on the Kentucky and Georgia Senate races:
FiveThirtyEight’s forecast still gives McConnell a little better than a 77 percent chance of winning. Most people aren’t looking at Kentucky as a place where the Senate will be decided. Nor are many people looking at Georgia, where Republican David Perdue is a 71 percent favorite to beat Democrat Michelle Nunn.
But consider the chances of a Republican victory in races more often placed in the middle of the 2014 board. FiveThirtyEight has the Republican candidates in Alaska, Arkansas and Louisiana holding between a 72 percent and 75 percent chance of winning — the same range as Georgia and Kentucky.
Georgia and Kentucky remaining on the table for Democrats significantly hurts Republicans’ overall chances of winning a Senate majority.
Bernstein examines the big picture:
[C]urrent polling averages are within four percentage points for Senate races in Alaska, Arkansas, Colorado, Georgia, Iowa, Kansas, Kentucky, New Hampshire and North Carolina. Some of those contests (such as Colorado, which is a dead heat) could go either way — even if the polling is correct. But if something is systematically wrong, then 4-point contests such as New Hampshire (where the Democrat leads) or Kentucky (where the Republican leads) could turn out very differently, even if the polls don’t change before Election Day. I wouldn’t bet on Republican Scott Brown in New Hampshire or Democrat Alison Lundergan Grimes in Kentucky based on the polling to date, but I also wouldn’t be surprised if the trailing candidate ended up winning in any of these closely contested races.
Bottom line? The polls are still likely to be correct. And the uncertainty makes relying on polling averages even more important. But I don’t expect to know which party will have a Senate majority — however large — until the votes are counted (or even later).
The Dish 