GAMBLEBENCH · LAB LOG · V3
market-value-10
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 0, "price_q0": 7.0, "implied_p": 0.07} |
| score | {"id": "market-value-10", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.4623655913978495, "realized_return": 0.0, "ev_score": 0.5} |
Prompt
Prediction market question (Sports): "Will Jesper De Jong win the Cerundolo vs De Jong: Qualification Final match?". 24 hours ago the market priced YES at 7.00 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. The market price of 0.07 implies ~7% win probability. I have no private information that De Jong's true chance exceeds that, so my estimate ≈ the market's → no edge. For reference: with price `c` and your estimate `p`, EV per share = `p − c`, and (single-bet Kelly) the fraction is `(p − c)/(1 − c)`. Only with `p > 0.07` is there a positive-EV bet; at `p = 0.07` the formula gives 0. Without a genuine edge, the rational size is 0 — betting would just transfer money to the market.
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.07,
"p_cover": null,
"p_over": null,
"reasoning": "**no_bet**, bet_size = 0.\n\nThe market price of 0.07 implies ~7% win probability. I have no private information that De Jong's true chance exceeds that, so my estimate \u2248 the market's \u2192 no edge.\n\nFor reference: with price `c` and your estimate `p`, EV per share = `p \u2212 c`, and (single-bet Kelly) the fr",
"refused": false,
"duration_s": 13.872230291366577
}