Donald Trump leapfrogs over Scott Walker to take huge lead in Iowa

First of all, I take this poll with a grain of salt.  For the following reasons.

1. Small sample (227 Republican caucus members), large margin of error (+/-6.5%)
2. Gravis has been taken to task more than once for its polling numbers.
3. With a few exceptions, previous Iowa polls so far this year have shown a general lack of  volatility in the percentages.
4. Bobby Jindal in 4th place?  His Iowa polling average is 2.5%.  His national average is 1.5%.

 Source of previous polls:  Real Clear Politics

The behinders in the latest Iowa Gravis Marketing poll:

• 5.5% - Ted Cruz
• 5.1% - Ben Carson
• 5.0% - John Kasich
• 4.3% - Carly Fiorina
• 2.9% - Rick Santorum
• 2,8% - Marco Rubio
• 1.7% - Rick Perry
• 1.0% - Lindsey Graham
• 0.8% - Chris Christie
• 0.8% - Rand Paul
• 0.6% - George Pataki

Other stuff:

• Of all respondents, 53% identify as pro-choice, 40% as pro-life.

More Iowa polling: 
Donald Trump threatens Scott Walker's lead in Iowa.  (7/27/2015)
Scott Walker treads water in Iowa Republican presidential caucus polls.  (7/11/2015)
Donald Trump places 2nd, behind Scott Walker, in latest Iowa Republican caucus poll.  (7/1/2015)
Scott Walker maintains lead in Iowa Republican presidential caucus polling.  (6/15/2015) 
Likely Iowa Republican caucus-goers are still groovin' on Scott Walker -- but not nearly as much as they were in February.  (6/4/2015)
Scott Walker finishes 1st in latest Iowa poll, but his best numbers are more than 3 months behind him.  (5/31/2015)
Rick Santorum: You ain't goin' nowhere in this presidential race.  (5/28/2015)
Kristina, 27, like the idea of Donald Trump running for President.  (5/23/2015)
Will the results of the August 2015 Iowa straw poll embarrass Republicans again?  (5/21/2015)
The Iowa straw poll, a slow death by many small cuts.  (5/21/2015)
Dreamboat Dixie channels Heart.  (5/17/2015)
Hey, Tanya, if you like Carly Fiorina, you'll love Scott Walker.  (5/17/2015)
Walt Rogers hitches his star to a political flameout.  (5/17/2015)
This Saturday, Republican presidential "wannabes" descend on Des Moines for "the fourth major, multi-candidate cattle call of the caucus campaign".  (5/14/2015) 
Jeb hurts Iowans' feelings.  (5/13/2015)
Pandering to social conservatives, Scott Walker and his buddies continue to box themselves into a corner.  (4/26/2015)
Let the intramural sniping begin.  (4/26/2015)
Reporter shares his sharp, blunt, candid assessment.  (4/26/2015)
'Veteran Republican Strategist' sez goodbye to Scott Walker the day after 'hello'. (3/18/2015)
Clothes make the man: The Iowa Caucus edition.  (3/18/2015)
Liz Mair stars in Scott Walker's 'Les Miz'.  (3/17/2015)
Motor runnin', Scott Walker gives a shout-out to these Iowa communities.  (3/9/2015)
Scott Walker serves up a helping of red meat to audience at Iowa Agriculture Summit.  (3/8/2015)
The insignificance of the Iowa caucus.  (3/7/2015)
Scott Walker is already booked, naturally, for the last weekend in April.  (3/3/2015)
Quinnipiac poll: Scott Walker is the Tea Party favorite among likely caucus-goers in Iowa.  (2/26/2015)
Mike Huckabee retakes Iowa lead, Walker falls to 3rd in NBC News/Marist poll.  (2/17/2015)