AP-GFK National: Clinton +15

[ProudModerate2]

Nate Cohn ‏@Nate_Cohn  1m1 minute ago Washington, DC
Key note on the AP/GfK poll: it's a probability sample conducted online. Yet Trump doesn't overperform.

Nate Cohn ‏@Nate_Cohn  1m1 minute ago Washington, DC
To be clearer: AP/GfK is a good test of "hidden Trump" vote theory. But it's now Trump's worst poll

Interesting.

[ProudModerate2]

538 is reporting this in their database with a Clinton +14, not a Clinton +15.
The difference (I think) is that 538 is using "Likely Voters" data, and not the "Total" numbers as posted in the OP (which I believe includes Registered Voters).

Here is the data for the 538 entry:
* GFK Group
* Sample 1,212 Likely Voters
* Oct 20-24

Clinton 51 (leads by +14)
Trump 37
Johnson 6
Stein 2

So it seems that a "trump at 37" is more believable than a "trump at 33."
Here is the link. Look at page 9.
http://ap-gfkpoll.com/main/wp-content/uploads/2016/10/October-2016-AP-GfK-Poll-Topline_Campaign.pdf