Why We Should Be Careful About The Quinnipiac Poll

I'm no pollster, but why has the Q-poll sample of black Dem likely voters dropped from 35% to 27% to 25% in last three polls?
— Nick Confessore (@nickconfessore) September 3, 2013

There's a lot of muttering around the Internets about that Quinnipiac poll out today showing de Blasio with a commanding lead in the Democratic primary for mayor.

They're polling fewer black voters (you can see the trajectory above - from 35% to 27% to 25%), which seems weird given the make-up of the Democratic electorate in the city.

Also there's an issue with how they're polling Hispanic voters:

@QuinnipiacPoll why don't you report data for Hispanic Origin in your NYC poll? @GersonBorrero @Azi @JuanMaBenitez http://t.co/01N3jSxZ1c
— Hector Cordero (@HCorderoGuzman) September 3, 2013

Plus the trajectory of de Blasio's support is like a rocket over the last four Q-polls - from 20% to 30% to 36% to 43%.

The Quinnipac poll had Bloomberg winning big in 2009 - he won by 5 percentage points - so they can get stuff wrong.

I think the de Blasio momentum is real - AM News/News 12 poll again showed de Blasio in the lead today and the Siena/Times poll also showed him leading.

But I am having a hard time believing the 43% level of support.

Let's see another poll with those kind of results before we take that to the bank.

Still, I think Quinn and Thompson are in trouble. 

That's why they're both aiming at de Blasio.

If they thought de Blasio was going to be kept under 40%, they'd be going at each other and trying to be that other candidate in the runoff.

That they're both going hard and heavy at de Blasio tells me they're both afraid they're going to miss the runoff completely.