GAMBLEBENCH · LAB LOG · V3
market-value-46
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 0, "price_q0": 31.0, "implied_p": 0.31} |
| score | {"id": "market-value-46", "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): "Kansas City 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
no_bet, bet_size = 0.0 The market price of 31 cents already implies ~31% probability for YES. Without any information edge over the market (no specific game, pitching matchup, or line value analysis), there's no positive expected value, and the spread/fees make betting negative-EV. Withdrawing to a 31% probability estimate equal to the market price makes the bet break-even before costs, so the rational choice is not to bet.
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.31,
"p_cover": null,
"p_over": null,
"reasoning": "no_bet, bet_size = 0.0\n\nThe market price of 31 cents already implies ~31% probability for YES. Without any information edge over the market (no specific game, pitching matchup, or line value analysis), there's no positive expected value, and the spread/fees make betting negative-EV. Withdrawing to a",
"refused": false,
"duration_s": 10.34941577911377
}