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2 pip or 1/2 pip crossover penalty

Posted By: Daniel Murphy
Date: Tuesday, 7 September 2010, at 6:19 p.m.

In Response To: 2 pip or 1/2 pip crossover penalty (Stanley E. Richards)

Oh, did my alter ego post that in 2006? I don't recall posting it, or the context. Maybe I'm smarter now, maybe not!

I haven't given much thought to crossovers in quite while. I don't recall ever using a formula that added X number of pips to account for a crossover.

What I do remember that a long time ago I thought they were usually important. Later, I was schooled to think they are usually not very important, unless they cost a roll. Better put, perhaps: they might usually have some importance in some sequences -- for example, if the sides need 7 and 9 crossovers to bear in, then sometimes that's going to cost the trailer a roll -- but when both sides are already in a roll vs. roll position, they're either not important if they don't cost a roll or extremely important if they do.

Repeating the diagram:

Blue on roll, cube decision?

White	61
Blue	57
Position ID: 224rAADb7g4AAA Match ID: cAkAAAAAAAAA

• In raw pip count, Blue leads by 4 pips, 57-61.
• Blue's wastage is 9.47.
• White's wastage is 10.73, or 1.26 higher.
• Blue's cubeless GWC is 77.7%
• Blue's cubeful equity after double/take is about +0.992

White, though, trails by 2 crossovers, 17-15. This means White is a roll behind. Is applying a penalty for the crossovers the best way to acknowledge that?

In a 57-61 race with equal crossovers, Blue's cubeless GWC would be about 70%.

In a 57-63 race with equal crossovers, Blue's cubeless GWC would be about 74%.

The position above, where White trails by 4 pips but is a roll behind, is more like trailing by 8 raw pips, 57-65. Two examples:

White	65
Blue	57
Position ID: VU0VANCqqgAAAA Match ID: cAkAAAAAAAAA

Blue's cubeless GWC is about 77.9%, and Blue's D/T equity is about +1.030.

White	65
Blue	57
Position ID: tXsPAADb7g4AAA Match ID: cAkAAAAAAAAA

Blue's cubeless GWC is about 77.5%, and Blue's D/T equity is about +0.990.

---

In the September 6 position, reposted below:

White	70
Blue	70
Position ID: tt0XAAC27Q8AAA Match ID: cAkAAAAAAAAA

White trails by a crossover that does not lose a roll, and any penalty for the crossover would be too much, because White actually has the lower Effective Pip Count. Blue wastes 8.17 pips, White only 8.02 pips.

Messages In This Thread

• 2 pip or 1/2 pip crossover penalty
  Stanley E. Richards -- Monday, 6 September 2010, at 11:46 a.m.
  • 2 pip or 1/2 pip crossover penalty
    Tom Keith -- Monday, 6 September 2010, at 12:48 p.m.
    • 2 pip or 1/2 pip crossover penalty
      Daniel Murphy -- Monday, 6 September 2010, at 7:12 p.m.
    • 2 pip or 1/2 pip crossover penalty
      Stanley E. Richards -- Tuesday, 7 September 2010, at 4:14 a.m.
      • 2 pip or 1/2 pip crossover penalty
        Daniel Murphy -- Tuesday, 7 September 2010, at 6:19 p.m.
  • 2 pip or 1/2 pip crossover penalty
    Chuck Bower -- Tuesday, 7 September 2010, at 4:39 p.m.
    • 2 pip or 1/2 pip crossover penalty
      Stanley E. Richards -- Wednesday, 8 September 2010, at 3:42 a.m.
  • 2 pip or 1/2 pip crossover penalty
    Chuck Bower -- Wednesday, 8 September 2010, at 4:51 p.m.
    • 2 pip or 1/2 pip crossover penalty
      Bob Koca -- Wednesday, 8 September 2010, at 9:31 p.m.