Is this the only recurring public poll that is polling likely voters?
Is that why Warren has more support than in other polls?
Very possible. Morning Consult, one of Warren's worst pollsters, polls only registered voters, whereas YouGov (one of her best) is a likely voter model. Change Research (by far her best) appears to poll likely voters at the state level but only registered in nationwide polls.
Also important to note that with likely voter samples, a lot of error can be attributed to assumptions and predictions made by the pollster regarding who will turn out. Whereas with registered voters, the universe is much more set in stone.
