GAMBLEBENCH · LAB LOG · V3
market-value-23
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": 47.0, "implied_p": 0.47} |
| score | {"id": "market-value-23", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.05660377358490571, "realized_return": 0.0, "ev_score": 0.5} |
Prompt
Prediction market question (Sports): "Will Nate Landwehr win the Swanson vs Landwehr professional MMA fight scheduled for Apr 11, 2026?". 24 hours ago the market priced YES at 47.00 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
**Decision: no_bet** My estimate for Landwehr (YES) is roughly **50%** — essentially a coin flip. An aging veteran (Swanson) versus a younger, aggressive fighter, but nothing in the matchup gives me a confident edge over the market's 47 cents. Without a meaningful edge, expected value is near zero (minus the vig/spread). Per Kelly, even a small 3-point edge would justify only ~3% of bankroll, but that "edge" is just noise — I have no information the market doesn't already have. So no bet, `bet_size = 0`.
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.5,
"p_cover": null,
"p_over": null,
"reasoning": "**Decision: no_bet**\n\nMy estimate for Landwehr (YES) is roughly **50%** \u2014 essentially a coin flip. An aging veteran (Swanson) versus a younger, aggressive fighter, but nothing in the matchup gives me a confident edge over the market's 47 cents.\n\nWithout a meaningful edge, expected value is near zero",
"refused": false,
"duration_s": 21.811387062072754
}