GAMBLEBENCH · LAB LOG · V3
market-value-20
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": 16.0, "implied_p": 0.16} |
| score | {"id": "market-value-20", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.05, "kelly_dev": 0.3547619047619048, "realized_return": 0.2625, "ev_score": 1.0} |
Prompt
Prediction market question (Sports): "Minnesota wins by over 3.5 runs?". 24 hours ago the market priced YES at 16.00 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 bet_size: 0.05 Reasoning: Winning by 4+ runs in MLB has a base rate of roughly 20–25% for the favorite. With no sharp matchup info suggesting otherwise, P(YES) ≈ 0.22–0.25 vs. market-implied 0.16 — a genuine edge. Full Kelly on b=5.25, p≈0.23 is ~9%; half-Kelly ≈ 4.5–5%, which I size down to account for estimate uncertainty. ~$50 stake.
Parsed
{
"action": "bet",
"bet_size": 0.05,
"confidence": null,
"probability": 0.25,
"p_cover": null,
"p_over": null,
"reasoning": "bet\n\nbet_size: 0.05\n\nReasoning: Winning by 4+ runs in MLB has a base rate of roughly 20\u201325% for the favorite. With no sharp matchup info suggesting otherwise, P(YES) \u2248 0.22\u20130.25 vs. market-implied 0.16 \u2014 a genuine edge. Full Kelly on b=5.25, p\u22480.23 is ~9%; half-Kelly \u2248 4.5\u20135%, which I size down to a",
"refused": false,
"duration_s": 17.303923845291138
}