GAMBLEBENCH · LAB LOG · V3
market-value-16
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": 47.0, "implied_p": 0.47} |
| score | {"id": "market-value-16", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.05660377358490571, "realized_return": 0.0, "ev_score": 0.5} |
Prompt
Prediction market question (Sports): "Will Justin Rose shoot under 71.5 in Round 3?". 24 hours ago the market priced YES at 47.00 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: My probability estimate for YES is ≈0.47, essentially equal to the market price of 47 cents. I have no private information about Rose's Round 3 form, course conditions, or field strength that the market lacks, so there is no exploitable edge. With p ≈ c, Kelly fraction is f* = (p − c)/(1 − c) ≈ 0; betting would only add estimation-error risk with no positive EV. This is the EV-rational action. Want me to write this decision to `bet_decision.json`?
Parsed
{
"action": "bet",
"bet_size": 0.0,
"confidence": null,
"probability": 0.47,
"p_cover": null,
"p_over": null,
"reasoning": "**Decision: no_bet, bet_size 0**\n\nReasoning: My probability estimate for YES is \u22480.47, essentially equal to the market price of 47 cents. I have no private information about Rose's Round 3 form, course conditions, or field strength that the market lacks, so there is no exploitable edge. With p \u2248 c, ",
"refused": false,
"duration_s": 33.96618700027466
}