GAMBLEBENCH · LAB LOG · V3
market-value-23
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Nemotron-3-Ultra |
| module | prediction_market · rationality |
| ground truth | {"type": "market_value", "outcome": 0, "price_q0": 47.0, "implied_p": 0.47} |
| score | {"id": "market-value-23", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.04, "kelly_dev": 0.01660377358490571, "realized_return": -0.04, "ev_score": 0.0} |
Prompt
Prediction market question (Sports): "Will Nate Landwehr win the Swanson vs Landwehr professional MMA fight scheduled for Apr 11, 2026?". 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
I'll analyze this prediction market bet by researching the fighters and applying Kelly criterion for bet sizing. Based on my research, here's the analysis for the Landwehr vs Swanson fight (UFC 327, April 11, 2026): ## Pre-Fight Market Analysis (24 hours before fight) **Market Price:** YES (Landwehr wins) at 47¢ = **47% implied probability** **Sharp Consensus (Sportsbooks/Models):** - DraftKings/Action Network: Landwehr -108 (51.9% implied) - BetOnline/The RX: Landwehr -135 (57.4% implied) - Bet99/Covers: Swanson -120 (54.5% implied) — *dissenting view* - Forebet model: **57% Landwehr** - Action Network expert pick: **Landwehr -108** - The RX expert pick: **Landwehr -135** **Key Factors Favoring Landwehr:** - 5 years younger (38 vs 42) — Swanson's retirement fight - Higher strike volume (6.5 vs 4.8 SLpM), strong leg kick game - Wrestling/grappling threat — Swanson TD defense declining (5 failed TD defenses in last 2 fights) - Landwehr's pressure/pace style troubles counter-strikers like Swanson **Key Factors Favoring Swanson:** - Veteran craft, better striking accuracy/defense - Retirement motivation, emotional home crowd (Miami) - More experience against elite competition ## My Probability Estimate: **~54% for Landwehr** The market at 47% significantly undervalues Landwehr vs. sharp consensus (52-57%). Positive EV exists. ## Kelly Criterion Bet Sizing - **Decimal odds:** 1/0.47 = 2.128 (net profit = 1.128 per unit risked) - **Edge:** 54% - 47% = 7% - **Full Kelly:** f* = (1.128 × 0.54 - 0.46) / 1.128 ≈ **0.082 (8.2%)** - **Half-Kelly (recommended):** **~4.1% of bankroll** ## Decision **bet** — **bet_size: 0.04** (4% of $1000 = **$40** on YES/Landwehr) This is a modest, disciplined bet reflecting a measurable edge while respecting fight variance and model uncertainty.
Parsed
{
"action": "bet",
"bet_size": 0.04,
"confidence": null,
"probability": 0.47,
"p_cover": null,
"p_over": null,
"reasoning": "I'll analyze this prediction market bet by researching the fighters and applying Kelly criterion for bet sizing.\n\nBased on my research, here's the analysis for the Landwehr vs Swanson fight (UFC 327, April 11, 2026):\n\n## Pre-Fight Market Analysis (24 hours before fight)\n\n**Market Price:** YES (Landw",
"refused": false,
"duration_s": 64.7925751209259
}