That Poll-Asked Look, Con't

It's time to start taking a serious look at the February primary and caucus contests, and it's still mostly a four-way contest in Iowa at this point, with Bernie on top at 20% and Biden, Buttigieg and Warren all within five.

U.S. Sen. Bernie Sanders leads the Democratic field three weeks ahead of Caucus Day in Iowa — narrowly overtaking his closest competitors, who remain locked in a tight contest just behind him.

A new Des Moines Register/CNN/Mediacom Iowa Poll shows 20% of likely Democratic caucusgoers name Sanders as their first choice for president.

After a surge of enthusiasm that pushed Pete Buttigieg to the top of the field in November, the former South Bend, Indiana, mayor has faded, falling 9 percentage points to land behind both Sanders and U.S. Sen. Elizabeth Warren. Warren is at 17%; Buttigieg, 16%; and former Vice President Joe Biden, 15%.

“There’s no denying that this is a good poll for Bernie Sanders. He leads, but it’s not an uncontested lead,” said pollster J. Ann Selzer, president of Selzer & Co., which conducted the poll. “He’s got a firmer grip on his supporters than the rest of his compatriots.”

The poll of 701 likely Democratic caucusgoers was conducted Jan. 2-8 and has a margin of error of plus or minus 3.7 percentage points.

Biden, Buttigieg, Sanders and Warren have remained clustered atop the Register’s Iowa Poll throughout the 2020 campaign cycle, though no one has definitively pulled away from the pack. Instead, each of the top four has now led the Iowa Poll at some point this cycle as the field continues to shift.

The percentage of those who say their mind is made up about which candidate to support on caucus night has risen to 40% — up 10 percentage points from November. But that leaves 45% who say they could still be persuaded to support someone else and another 13% who have not picked a favorite candidate yet.

Iowa is looking like anyone's game at this point, and as Nate Silver points out, Biden is the favorite but not a runaway one...yet.

Joe Biden is the most likely person to win a majority of pledged Democratic delegates, according to the FiveThirtyEight primary model, which we launched on Thursday morning. This is our first-ever full-fledged model of the primaries and we’re pretty excited about it — to read more about how the model works, see here.

But saying the former vice president is the front-runner doesn’t really tell the whole story. He may be the most likely nominee, but he’s still a slight underdog relative to the field, with a 40 percent chance of winning a majority of pledged delegates1 by the time of the last scheduled Democratic contest — the Virgin Islands caucus on June 6. If one lowers the threshold to a plurality of delegates, rather than a majority, then Biden’s chances are almost 50-50, but not quite — he has a 45 percent chance of a delegate plurality, per our forecast.

I want to emphasize that there’s still a lot of room for another candidate to surge because nobody has voted yet, the primaries are a complex process, and frankly here at FiveThirtyEight, we’re a little self-conscious about how people interpret — or sometimes misinterpret — our probabilistic forecasts. The Democratic primary still features 14 candidates, and while most of them have little to no shot, there are still several fairly realistic possibilities.

 

So while Biden’s in a reasonably strong and perhaps even slightly underrated position, it’s slightly more likely than not that Biden won’t be the nominee. Sen. Bernie Sanders has the next-best shot, with a 22 percent chance at a majority, followed by Sen. Elizabeth Warren at 12 percent and former Mayor Pete Buttigieg at 10 percent. There’s also a 14 percent chance — about 1 in 7 — that no one will win a majority of pledged delegates by June 6, which could lead to a contested convention.

The model works by simulating the nomination race thousands of times, accounting for the bounces that candidates may receive by winning or losing states, along with other contingencies — such as candidates dropping out and polls moving in response to debates and news events. Like all of our models, it’s empirically driven, built using data from the 15 competitive nomination races since 1980.2

Since the primaries themselves are fairly complex process, the model is fairly complex also — which we mean as a warning as much as a brag. Models with more complexity are easier to screw up and can be more sensitive to initial assumptions — so we’d encourage you to read more about how our model works.

As an illustration of how one race can affect the following ones in our model, here are each of the leading candidates’ chances of winning a plurality or majority of delegates conditional on winning or losing Iowa.

 

So if Biden does win Iowa, his odds go up from about 40% to about 80%. 

Whoever wins Iowa is the favorite, period.

We'll see if that holds up.  Most primary years like this it does.

But that was before Trump came along.