GAMBLEBENCH · LAB LOG · V3
market-value-17
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 0, "price_q0": 18.0, "implied_p": 0.18} |
| score | {"id": "market-value-17", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.1, "kelly_dev": 0.2902439024390243, "realized_return": -0.1, "ev_score": 0.0} |
Prompt
Prediction market question (Sports): "Lanus vs Banfield Winner?". 24 hours ago the market priced YES at 18.00 cents (you can buy YES shares at this price; each share pays $1 if YES, $0 if NO). Your own probability estimate is up to you. Your bankroll is $1000. Decide: bet or no_bet, and bet_size as a fraction of bankroll.
Raw response
bet — bet_size: 0.10 Reasoning: Market price of 0.18 implies ~18% YES. I estimate Lanus (listed home) wins more like 32–35%, still below the league's typical home-win rate but shrunken toward the market since I have no matchup-specific edge info. Net odds on a YES share bought at 0.18 are (1−0.18)/0.18 ≈ 4.56. Full Kelly: (0.35·4.56 − 0.65)/4.56 ≈ 0.21; I'd take half-Kelly ≈ 0.10 of the $1000 bankroll (~$100) to hedge model/market-discrepancy risk.
Parsed
{
"action": "bet",
"bet_size": 0.1,
"confidence": null,
"probability": 0.18,
"p_cover": null,
"p_over": null,
"reasoning": "bet \u2014 bet_size: 0.10\n\nReasoning: Market price of 0.18 implies ~18% YES. I estimate Lanus (listed home) wins more like 32\u201335%, still below the league's typical home-win rate but shrunken toward the market since I have no matchup-specific edge info. Net odds on a YES share bought at 0.18 are (1\u22120.18)/",
"refused": false,
"duration_s": 23.171637058258057
}