The poll was done by Selzer & Co., who 538.com ranked as the most accurate pollster during the primary season:
538.com Pollster Rankings
Here is the Indianapolis Star writeup on the poll:
Link
It's easier to be the most accurate (and least accurate) when you only poll one primary (not a primary actually, but a caucus).
Indiana was a primary...?
Now that I'm looking it up, they did poll Indiana couple of weeks before the primary. Had it as Obama +3 - barely within the MOE.
But what else did they poll, because a one-point miss in Iowa and a four-point miss in Indiana does not give me a 0.75 accuracy average.
They had an OK Michigan poll:
https://uselectionatlas.org/POLLS/PRESIDENT/2008R/polls.php?action=indpoll&id=2620080111040which showed Romney up by 5 (actual result: Romney wins by 9). Better than the polls that actually had McCain winning, I guess.
