You have regional scouts scouring the players in the different areas. Scouts over them. Scouts cross evaluating the work of others too I am sure. And having a system where they internally evaluate every player from watching all their snaps and including all the other info they have access to like medical, personalities, family, friends, etc., etc. So it's definitely night and day difference between teams and media types.
This is why I enjoy reading fans who do this, by the way. Because they probably put more effort into it than many of those in the media. It's a lot of work. I don't stack a board for that reason, it's way easier to just watch some tape on the position groups that interest me for the Rams.
The combine you definitely see a lot of juggling every year as the media types find out the scouts have guys in different spots. So this is why I like to disregard some of the slotting you have early on in the offseason. Those lists are good for reference on who to look at. But beyond that I find once I watch the players that I often disagree with how the media slots them.
But that's also what makes this so fun. Nobody's gonna bat a thousand. Even the teams are going to get a lot of them wrong. So even the most casual observer of a fan might end up being right.