It's a mix of coaches/team reps from across the country and me, I believe. There's one USCHO staff member responsible for the polls (it is not me) and they do a very good job of curating the list. We had a discussion about who to invite when we decided to expand to 15 teams. They also reached out to coaches who weren't good at replying and told them to send it in or get removed.
I will say this early on, with the Ivies not even on the ice yet, it's pretty impossible to really figure out a poll. I'd expect to see more movement over the next month. We've had very few ranked teams playing each other and so far we don't have a lot of useful information on the top teams.
For my own part, I've struggled a bit with the last few spots in the expanded poll. If a team losses, it sure feels like that team should move down or off the poll, right? It's more clear at the top when you're talking undefeated teams, but for 11-15, you're likely talking a team with losses and then you're comparing the relative badness of those losses, again with limited data. Like, even with a number of games under their belts, do I have a firm handle on Wisconsin based on series with Lindenwood, St. Thomas and now this weekend St. Cloud State? Just because they have some data points doesn't mean they add up to anything useful in the greater scheme of things. And a team like Minnesota State has looked very good against top teams, but ultimately is 0-4.
I don't know if other people think about it this much, but I promise you I do. I vote in both our poll and the USA Hockey/USA Today poll and I think about all these things and more before I submit my ballot.