GAMBLEBENCH · LAB LOG · V3
market-value-37
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 0, "price_q0": 11.0, "implied_p": 0.11} |
| score | {"id": "market-value-37", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.045, "kelly_dev": 0.39320224719101127, "realized_return": -0.045, "ev_score": 0.0} |
Prompt
Prediction market question (Sports): "Shimane Susanoo Magic vs Alvark Tokyo Winner?". 24 hours ago the market priced YES at 11.00 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 ≈ **0.045** (≈ $45) Reasoning: - Market price q = 0.11 implies ~11% chance YES (Shimane Susanoo Magic wins). - My estimate: p ≈ 0.15. Alvark is the clear favorite (34-14, 4th East vs Shimane 23-28, 8th West, and just beat them 65-52 at Toyota Arena), but Shimane has won 8 of 21 H2H and is a competitive B.League side — the ~11.5-point spread implies roughly an 85/15 split, so ~15% feels slightly better than the market's 11%. - Positive edge (p > q) → bet. Kelly fraction: f* = (p − q)/(1 − q) = 0.04/0.89 ≈ **4.5%** of the $1,000 bankroll.
Parsed
{
"action": "bet",
"bet_size": 0.045,
"confidence": null,
"probability": 0.11,
"p_cover": null,
"p_over": null,
"reasoning": "**bet** \u2014 bet_size \u2248 **0.045** (\u2248 $45)\n\nReasoning:\n- Market price q = 0.11 implies ~11% chance YES (Shimane Susanoo Magic wins). \n- My estimate: p \u2248 0.15. Alvark is the clear favorite (34-14, 4th East vs Shimane 23-28, 8th West, and just beat them 65-52 at Toyota Arena), but Shimane has won 8 of 21 ",
"refused": false,
"duration_s": 38.246389865875244
}