There's buzz this morning about a new CBS/New York Times national poll that shows Ben Carson leading Donald Trump by 4 percentage points. It's the first time since mid-July that a pollster that puts out results regularly has shown anyone but Trump leading the Republican primary nationally. "Peak Trump" has been declared, erroneously, almost as many times as "peak oil." Is there reason to believe it's real this time?
I often refer to polling averages such as the ones on Real Clear Politics and Huffington Post because they're useful for seeing the state of the horse race in a way that minimizes the effects of outlier polls. But today I want instead to look at trend lines in several polls individually to see how pollsters, using their same methodology each time, are tracking the race over time. I selected the six national pollsters that (per RCP) have reported results sometime in October, and looked at their results going back to before Trump officially entered the race (I stopped at May 31 since that gave me a pre-entrance result for all but CBS, which didn't put out a poll until August). Here are two charts showing what I found.
First, Trump's own result in each poll:
As you can see, Trump skyrocketed early on, then grew more gradually until mid- to late September. Since then, he has fallen in four of the six polls. Now let's look at his leads in the six polls (a negative number represents the distance between him and the leader of the poll):
Here, you can see that in five of the six polls, Trump's lead has shrunk during the past month or two. The exception is the NBC/WSJ poll, which showed his lead recovering slightly in October but still below its late-July peak. In the five polls in which he still leads, three of those leads are down to the low single-digits.
The polling average, which incorporates other polls as well, shows Trump below his mid-September peak but also his recent trough a couple of weeks ago. If individual polls continue to trend downward for him, however, we can probably expect the polling average to fall over time, too.
Of course, with a debate coming up tomorrow night, we'll soon have another inflection point in the race that could either put Trump back on an upswing or firm up his swoon. As Carson has been the only candidate to gain any strong momentum lately -- Marco Rubio has seen a steady uptick in polling averages over the past month, Carly Fiorina has fallen back after a sharp increase following the last debate, and Jeb Bush continues to fall steadily -- it'll be interesting to see if a strong debate from him would turn him into a consensus leader in the polls, or if a weak one would shift momentum back to Trump or to someone new.