"No, what I think is that usually market losers and winning percentages go hand in hand".
If it is a backgame and there is no immediate double shot where is the market loser?
"Think of it this way: Assuming the game would turn out to 40-60 with 20% vs 55% gammons. Clearly white's Match winning chances are <40% because of the gmmmons. The redouble brings it to 40% sharp hence a clear gain in equity."
What you say is clear is just wrong. You are incorrectly analyzing it as a double now or never situation.
How do you explain the following rollout result? An opponent's 54 is a market loser. The backgame players gammon rate is 4.0% which is less than your proposed 20%. That argues FOR doubling compared to your 20% since he is killing less of his own gammons. The attackers gammon rate is 62.5% which is more than your proposed 55%. That also argues FOR doubling since more of the opponent's gammons are killed. The win percentage is 44.1% which is more than your proposed 40% which also argues FOR doubling. Everything from your proposed situation moves it towards the double being correct but the rollout shows doubling is an error.
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| XGID=-B-BB-B----------CbbddBcB-:1:1:1:00:0:1:0:4:10 | |||||
| Blue on roll, cube action? | |||||
| Analyzed in Rollout | No redouble | Redouble/Take |
| Player Winning Chances: | 43.939% (G:1.992% B:0.058%) | 44.056% (G:1.770% B:0.041%) |
| Opponent Winning Chances: | 56.061% (G:34.338% B:13.984%) | 55.944% (G:34.964% B:14.065%) |
| Cubeless Equities | -0.3907 | +0.2320 |
| Cubeful Equities | ||
| No redouble: | +0.2448 | ±0.0071 (+0.2377..+0.2519) |
| Redouble/Take: | +0.2320 (-0.0128) | ±0.0073 (+0.2247..+0.2393) |
| Redouble/Pass: | +1.0000 (+0.7552) | |
| Best Cube action: No redouble / Take | ||
| Percentage of wrong pass needed to make the double decision right: 1.6% | ||
| Rollout details | ||
| 5184 Games rolled with Variance Reduction. Dice Seed: 39052828 Moves: 3-ply, cube decisions: XG Roller | ||
| Double Decision confidence: | 99.3% | |
| Take Decision confidence: | 100.0% | |
| Duration: 42 minutes 22 seconds | ||
eXtreme Gammon Version: 2.10, MET: Kazaross XG2