The best predictor of a season is that portion of the roster which returned from the previous season. At the top end - the teams who recruit 5* players - there is obviously a lot of wiggle room as one class is replaced with another loaded class. But you don't have to go far down the list before those outliers begin to disappear. Who returns matters.
But how do you evaluate the impact of those who returned? Typically, people talk about Team X losing "XX% of their scoring" or something like that. And while that is interesting, it doesn't really tell you much.
To remedy this I've borrowed a stat from our friend John Templon over at Big Apple Buckets. He calls it "returning possession minutes" or RPM. RPMs are simply a players % of minutes played the previous season, multiplied by the % of possessions he used. For example, Mason Plumlee played 86.7% of Duke's minutes, and while on the floor he was responsible for 25.2% of their possessions. His RPMs would be 21.8 (86.7 x 25.2/100). If a team returned their entire roster, their RPMs would total 100.
Here are the returning possession minutes for each team:
Boston College may have gone 7-11 in the ACC last year, but they basically return everyone. They should see a good jump this season. On the other end of the spectrum are NC State and Miami, who both lost a ton.
The other teams that really jump out are Virginia and Notre Dame. Both of them return >75% of their possession minutes, and both of them were solid teams last year. Virginia lost two starters - one to graduation and one to transfer. But neither of them were high volume players. Jontel Evans played 54% of the minutes and used 17.5% of the possessions. And Paul Jesperson played a few more minutes (64.1%) but was basically invisible beyond his 3-point shooting (11.8% of the possessions). Notre Dame lost one starter, but he was a big one. Jack Cooley played 71% of the minutes and used 23% of the possessions. He'll be missed, but they have plenty of experienced players to make up for it.
Duke and Syracuse, who are the favorites in the conference, will both be relying on new players to carry much of the load. Both return less than half their possession minutes, but both have loaded rosters. Still, it's easier to project Boston College (solid) or Virginia (very good) because we know exactly what they have. It's probably safe to assume that Duke and Syracuse are going to battle it out for conference supremacy, but with so many new guys in new roles, it's harder to project exactly how good they're going to be.
Here are the top 10 individual RPMs in the ACC:
1. Ryan Anderson, Boston College, 21.8
2. Jerian Grant, Notre Dame, 21.5
3. Joe Harris, Virginia, 21.3
4. Olivier Hanlan, Boston College, 20.8
5. James Michael McAdoo, North Carolina, 20.4
6. Akil Mitchell, Virginia, 18.9
7. Quinn Cook, Duke, 17.8
8. CJ Fair, Syracuse, 17.8
9. Dezmine Wells, Maryland, 17.7
10. Eric Atkins, Notre Dame, 17.6