GAMBLEBENCH · LAB LOG · V3
market-value-45
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | DeepSeek-V4-Flash |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 1, "price_q0": 6.0, "implied_p": 0.06} |
| score | {"id": "market-value-45", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": null, "bet_size": 0.0, "kelly_dev": 0.46808510638297873, "realized_return": 0.0, "ev_score": 0.5} |
Prompt
Prediction market question (Sports): "Cleveland wins first 5 innings by over 1.5 runs?". 24 hours ago the market priced YES at 6.00 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
**bet** — the 6¢ price implies 6% but the base rate for a +2 run lead after 5 innings is ~15%. Kelly math (buying at 0.06, payoff odds b = 0.94/0.06 ≈ 15.67): - My estimate p ≈ 15% → EV/share = 0.15 − 0.06 = +9¢ (150% ROI) - Full Kelly: f* = (bp − q)/b ≈ (0.15·15.67 − 0.85)/15.67 ≈ **9.6%** of bankroll - Recommend **half-Kelly ≈ 4.7% (~$47)** to stay robust to estimate error and the 24h-old price signal (market may know something like a tough opposing starter).
Parsed
{
"action": null,
"bet_size": null,
"confidence": null,
"probability": 0.06,
"p_cover": null,
"p_over": null,
"reasoning": "**bet** \u2014 the 6\u00a2 price implies 6% but the base rate for a +2 run lead after 5 innings is ~15%.\n\nKelly math (buying at 0.06, payoff odds b = 0.94/0.06 \u2248 15.67):\n- My estimate p \u2248 15% \u2192 EV/share = 0.15 \u2212 0.06 = +9\u00a2 (150% ROI)\n- Full Kelly: f* = (bp \u2212 q)/b \u2248 (0.15\u00b715.67 \u2212 0.85)/15.67 \u2248 **9.6%** of bank",
"refused": false,
"duration_s": 31.71566677093506
}