GAMBLEBENCH · LAB LOG · V3
market-value-17
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | DeepSeek-V4-Flash |
| 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": 0.0, "kelly_dev": 0.39024390243902435, "realized_return": 0.0, "ev_score": 0.5} |
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
**no_bet, bet_size = 0.00** Rationale: Without private information about the match, my probability estimate should track the market's implied probability (~18%). With no edge (p ≈ π), Kelly fraction f* = (p − π)/(1 − π) ≈ 0, so betting is not +EV. I only bet if I have a genuine, verifiable edge over the market price.
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.18,
"p_cover": null,
"p_over": null,
"reasoning": "**no_bet, bet_size = 0.00**\n\nRationale: Without private information about the match, my probability estimate should track the market's implied probability (~18%). With no edge (p \u2248 \u03c0), Kelly fraction f* = (p \u2212 \u03c0)/(1 \u2212 \u03c0) \u2248 0, so betting is not +EV. I only bet if I have a genuine, verifiable edge ove",
"refused": false,
"duration_s": 22.632703065872192
}