          
 
         
 | | White is Player 2
score: 0
pip: 119 | Unlimited Game
Jacoby Beaver | pip: 185
score: 0
Blue is Player 1 |
|
| XGID=-----AC-C-bBaB--abcbbbBB--:1:1:1:61:0:0:3:0:10 |
| Trail by 66 pips: Don't Hit |
| 1. | XG Roller++ | 11/5 8/7 | eq: -0.331 |
| Player:
Opponent: | 35.75% (G:4.33% B:0.14%)
64.25% (G:22.95% B:1.04%) | |
|
| 2. | XG Roller++ | 22/16* 6/5 | eq: -0.533 (-0.203) |
| Player:
Opponent: | 30.55% (G:5.27% B:0.23%)
69.45% (G:29.14% B:2.02%) | |
|
These are only ++ evaluations, but they give a sense of what's going on. In the original position above, Black trails by 66 pips, and the eval prefers not hitting by .203 (roughly the same margin as in Stick's very short rollout).
I'll quote Tim quoting the book Backgammon Masterclass:"...the minimum pip deficit required to take a 2-3 backgame is 48 pips."
FWIW, the positions shown below, where Blue trails by 48, are passes by about .040 according to the eval. I did an (admittedly weak 3-ply) 5k rollout on the first, resulting in a pass by .077. (This does not necessarily contradict the book, which refers to a minimum.)
The take/pass cusp is a different issue than whether one should try to break out of a backgame, given that there are many factors to weigh. But it does happen that 48 is a pretty fair cusp for this situation.
In the first position below, according to ++ eval, Black should not hit (by .022). In the second position below, Black should hit (by .071). Smoothness is a sensitive factor.
Nack
  
| | White is Player 2
score: 0
pip: 127 | Unlimited Game
Jacoby Beaver | pip: 175
score: 0
Blue is Player 1 |
|
| XGID=-----ADC-Ac-aB--abbbbbBB--:1:1:1:61:0:0:3:0:10 |
| Trail by 48 pips: Don't Hit, but close |
| 1. | XG Roller++ | 9/3 6/5 | eq: -0.656 |
| Player:
Opponent: | 23.69% (G:2.27% B:0.09%)
76.31% (G:24.05% B:0.93%) | |
|
| 2. | XG Roller++ | 22/16* 6/5 | eq: -0.678 (-0.022) |
| Player:
Opponent: | 25.09% (G:4.49% B:0.19%)
74.91% (G:29.96% B:2.00%) | |
|
| | White is Player 2
score: 0
pip: 127 | Unlimited Game
Jacoby Beaver | pip: 175
score: 0
Blue is Player 1 |
|
| XGID=-----ADBB-c-aB--abbbbbBB--:1:1:1:61:0:0:3:0:10 |
| Trail by 48 pips, but smooth: Hit |
| 1. | XG Roller++ | 22/16* 6/5 | eq: -0.588 |
| Player:
Opponent: | 27.45% (G:5.48% B:0.24%)
72.55% (G:27.70% B:1.78%) | |
|
| 2. | XG Roller++ | 8/2 6/5 | eq: -0.659 (-0.071) |
| Player:
Opponent: | 23.60% (G:2.25% B:0.08%)
76.40% (G:24.08% B:0.93%) | |
|