GAMBLEBENCH · LAB LOG · V3

market-value-40

RECORDED 03 AUG 2026 RUN V3
fieldvalue
subjectBig-Pickle
moduleprediction_market · rationality
ground truth{"type": "market_value", "outcome": 1, "price_q0": 45.0, "implied_p": 0.45}
score{"id": "market-value-40", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.09090909090909088, "realized_return": 0.0, "ev_score": 0.5}

Prompt

Prediction market question (Sports): "Philadelphia at Winnipeg Winner?". 24 hours ago the market priced YES at 45.00 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

My probability estimate: ~45% (matching the efficient market, which already accounts for Winnipeg's home ice).

No edge → no_bet, bet_size = 0. Betting without a probability advantage over the market price just bleeds the bid/ask spread.

Parsed

{
 "action": "bet",
 "bet_size": 0.0,
 "confidence": null,
 "probability": 0.45,
 "p_cover": null,
 "p_over": null,
 "reasoning": "My probability estimate: ~45% (matching the efficient market, which already accounts for Winnipeg's home ice).\n\nNo edge \u2192 no_bet, bet_size = 0. Betting without a probability advantage over the market price just bleeds the bid/ask spread.",
 "refused": false,
 "duration_s": 11.331944942474365
}