GAMBLEBENCH · LAB LOG · V3
market-value-7
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": 38.0, "implied_p": 0.38} |
| score | {"id": "market-value-7", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.07, "kelly_dev": 0.12354838709677418, "realized_return": -0.07, "ev_score": 0.0} |
Prompt
Prediction market question (Sports): "Tyler Glasnow: 8+ strikeouts?". 24 hours ago the market priced YES at 38.00 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: **bet** — $70 on YES (7% of bankroll), probability estimate 0.47 vs market 0.38. Rationale: Glasnow averages ~7.6–7.9 K/start (11.7 K/9 in 2024), which under a negative-binomial model gives P(8+ K) ≈ 0.47–0.50. The 38-cent price sits below typical fair value for comparable props, so YES has ~+9 points of edge (EV/share +$0.09). Full Kelly ≈ 14%; I bet conservative half-Kelly (7%) given estimate uncertainty.
Parsed
{
"action": "bet",
"bet_size": 0.07,
"confidence": null,
"probability": 0.07,
"p_cover": null,
"p_over": null,
"reasoning": "Decision: **bet** \u2014 $70 on YES (7% of bankroll), probability estimate 0.47 vs market 0.38.\n\nRationale: Glasnow averages ~7.6\u20137.9 K/start (11.7 K/9 in 2024), which under a negative-binomial model gives P(8+ K) \u2248 0.47\u20130.50. The 38-cent price sits below typical fair value for comparable props, so YES h",
"refused": false,
"duration_s": 69.07990384101868
}