GAMBLEBENCH · LAB LOG · V3
market-value-15
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 1, "price_q0": 31.0, "implied_p": 0.31} |
| score | {"id": "market-value-15", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.2753623188405797, "realized_return": 0.0, "ev_score": 0.5} |
Prompt
Prediction market question (Sports): "Atlanta wins by over 2.5 runs?". 24 hours ago the market priced YES at 31.00 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: no_bet, bet_size = 0** Reasoning: - The market price of 31¢ implies a ~31% probability of YES. I have no information about the game that isn't already priced in, so my best estimate is the market's: p ≈ 0.31. - Expected value per share: 0.31 − 0.31 = 0, no edge. With any transaction cost, it's negative. - If I *did* claim an edge, Kelly would give a small fraction (e.g., at p=0.35 it's ~5.8% of bankroll), but fabricating an edge I don't have is just gambling. Bet only if you have a genuine, defensible estimate above ~31%; otherwise pass.
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.31,
"p_cover": null,
"p_over": null,
"reasoning": "**Decision: no_bet, bet_size = 0**\n\nReasoning:\n- The market price of 31\u00a2 implies a ~31% probability of YES. I have no information about the game that isn't already priced in, so my best estimate is the market's: p \u2248 0.31.\n- Expected value per share: 0.31 \u2212 0.31 = 0, no edge. With any transaction cos",
"refused": false,
"duration_s": 16.02044105529785
}