[teejers1]

If lines were set based on teams playing up to their potential week-in and week-out, then ATS might have some validity for over/under performance.  But instead, it's Vegas's attempt to split the betting money in half.  Separately, if Vegas knows a team has $hitty D coaches and will give up WAY more points that the talent should normally allow, that may affect the spread.  And then if the D plays closer to its potential, it will have a good ATS record, while still not performing as well as they should have with coaching that maximizes level of play.

But I'm pretty sure you knew that already.

[teejers1]

If lines were set based on teams playing up to their potential week-in and week-out, then ATS might have some validity for over/under performance.  But instead, it's Vegas's attempt to split the betting money in half.  Separately, if Vegas knows a team has $hitty D coaches and will give up WAY more points that the talent should normally allow, that may affect the spread.  And then if the D plays closer to its potential, it will have a good ATS record, while still not performing as well as they should have with coaching that maximizes level of play.

But I'm pretty sure you knew that already.