GAMBLEBENCH · LAB LOG · V3
market-pricing-57
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | DeepSeek-V4-Flash |
| module | prediction_market · rationality |
| ground truth | {"type": "market_pricing", "outcome": 0, "price_q": 71.0, "implied_p": 0.71} |
| score | {"id": "market-pricing-57", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "brier": 0.25, "prob_error": 0.5, "calibration_bin": 5} |
Prompt
Prediction market question (Sports): "Valero Texas Open: Will J.T. Poston finish top 20?". The market currently prices YES at 71.00 cents (implied probability 0.710). What is YOUR probability that this market resolves YES? Your bankroll is $1000.
Raw response
My probability: **~0.42** (I'd bet NO). Reasoning: Top-20 in a ~150-man field is a high bar; even an in-form top-60 player like Poston typically sits well under 50% to crack the top 20. The 0.71 price looks meaningfully overpriced, so YES at 0.71 has negative EV. Buying NO at 0.29 is positive EV (edge ≈ +0.07 per dollar risked); a half-Kelly stake is ~$220.
Parsed
{
"action": "bet",
"bet_size": null,
"confidence": null,
"probability": 0.5,
"p_cover": null,
"p_over": null,
"reasoning": "My probability: **~0.42** (I'd bet NO).\n\nReasoning: Top-20 in a ~150-man field is a high bar; even an in-form top-60 player like Poston typically sits well under 50% to crack the top 20. The 0.71 price looks meaningfully overpriced, so YES at 0.71 has negative EV. Buying NO at 0.29 is positive EV (e",
"refused": false,
"duration_s": 22.64089798927307
}