GAFFER vs the market · Kalshi
Were we right?
Every match — group and knockout — our pre-match odds set against Kalshi's pre-match price. Two scorelines: who forecast better (de-vigged Brier & log-loss), and how a bankroll backing our disagreements into Kalshi's real, vig-inclusive prices would have done.
Forecast accuracy69 games
Market ahead
metricGAFFERMarket
Brier0.3980.364
Log-loss0.6670.625
Hit rate0.7390.754
Lower Brier & log-loss = sharper. Market price is de-vigged to a fair probability first. Green marks the better of the two.
Flat stake · with vig$6,100 risked
−$0
0.0% ROI
0–0
Record
0%
Hit rate
Kelly bankroll · with vig0.5× Kelly
$0
from $1,000 · -37.7%
Compounds a $1,000 bankroll, sizing each bet by 0.5× the Kelly edge. Sensitive to model overconfidence & thin liquidity — treat as a ceiling.
Match by match
The ledger
our odds vs the market · the actual result is the bright segment
Jun 19
2–0
United States
2–0GAFFER52%
Market60%
Draw @ 0.22 · edge +4.2%
−$100
Jun 19
0–1
Morocco
0–1GAFFER49%
Market58%
Draw @ 0.27 · edge +5.4%
−$100
Jun 19
3–0
Brazil
3–0GAFFER89%
Market88%
no edge · pass
Jun 19
0–1
Paraguay
0–1GAFFER25%
Market24%
no edge · pass
Jun 20
5–1
Netherlands
5–1GAFFER57%
Market57%
no edge · pass
Jun 20
2–1
Germany
2–1GAFFER51%
Market69%
Ivory Coast @ 0.13 · edge +9.1%
−$100
Jun 20
0–0
Draw
0–0GAFFER16%
Market10%
Draw @ 0.11 · edge +5.4%
+$809
Jun 20
0–4
Japan
0–4GAFFER55%
Market69%
Draw @ 0.21 · edge +7.5%
−$100
Jun 21
4–0
Spain
4–0GAFFER84%
Market88%
Draw @ 0.08 · edge +4.7%
−$100
Jun 21
0–0
Draw
0–0GAFFER22%
Market20%
Iran @ 0.11 · edge +2.4%
−$100
Jun 21
2–2
Draw
2–2GAFFER28%
Market22%
Draw @ 0.23 · edge +4.6%
+$335
Jun 21
1–3
Egypt
1–3GAFFER51%
Market61%
Draw @ 0.24 · edge +9.2%
−$100
Jun 22
2–0
Argentina
2–0GAFFER55%
Market68%
Draw @ 0.21 · edge +8.0%
−$100
Jun 22
3–0
France
3–0GAFFER86%
Market96%
Draw @ 0.04 · edge +6.8%
−$100
Jun 22
3–2
Norway
3–2GAFFER40%
Market42%
no edge · pass
Jun 22
1–2
Algeria
1–2GAFFER72%
Market64%
Algeria @ 0.65 · edge +7.2%
+$54
Jun 23
5–0
Portugal
5–0GAFFER71%
Market85%
Draw @ 0.11 · edge +9.0%
−$100
Jun 23
0–0
Draw
0–0GAFFER21%
Market11%
Draw @ 0.12 · edge +8.9%
+$733
Jun 23
0–1
Croatia
0–1GAFFER74%
Market68%
Croatia @ 0.68 · edge +5.8%
+$47
Jun 23
1–0
Colombia
1–0GAFFER54%
Market64%
Draw @ 0.24 · edge +5.5%
−$100
Jun 24
1–2
Switzerland
1–2GAFFER40%
Market39%
Canada @ 0.30 · edge +2.3%
−$100
Jun 24
3–1
Bosnia and Herzegovina
3–1GAFFER59%
Market70%
Qatar @ 0.12 · edge +5.3%
−$100
Jun 240–3Brazil
0–3GAFFER66%
Market74%
Scotland @ 0.09 · edge +3.3%
−$100
Jun 244–2Morocco
4–2GAFFER72%
Market79%
Draw @ 0.15 · edge +5.3%
−$100
Jun 24
1–0
South Africa
1–0GAFFER21%
Market16%
South Africa @ 0.16 · edge +5.0%
+$525
Jun 24
3–0
Mexico
3–0GAFFER48%
Market56%
Draw @ 0.23 · edge +3.7%
−$100
Jun 250–2Ivory Coast
0–2GAFFER78%
Market81%
Draw @ 0.13 · edge +3.6%
−$100
Jun 252–1Ecuador
2–1GAFFER24%
Market19%
Draw @ 0.21 · edge +9.5%
−$100
Jun 251–3Netherlands
1–3GAFFER71%
Market88%
Draw @ 0.09 · edge +10.2%
−$100
Jun 251–1Draw
1–1GAFFER27%
Market28%
Sweden @ 0.28 · edge +3.7%
−$100
Jun 250–0Draw
0–0GAFFER35%
Market42%
Australia @ 0.23 · edge +7.1%
−$100
Jun 252–3Turkey
2–3GAFFER34%
Market26%
Turkey @ 0.26 · edge +7.6%
+$285
Jun 261–4France
1–4GAFFER52%
Market71%
Norway @ 0.13 · edge +10.3%
−$100
Jun 265–0Senegal
5–0GAFFER70%
Market78%
Draw @ 0.14 · edge +7.5%
−$100
Jun 260–0Draw
0–0GAFFER34%
Market29%
Draw @ 0.29 · edge +5.4%
+$245
Jun 260–1Spain
0–1GAFFER53%
Market59%
Uruguay @ 0.15 · edge +3.0%
−$100
Jun 261–5Belgium
1–5GAFFER79%
Market81%
Draw @ 0.12 · edge +3.6%
−$100
Jun 261–1Draw
1–1GAFFER34%
Market35%
no edge · pass
Jun 270–2England
0–2GAFFER85%
Market85%
no edge · pass
Jun 272–1Croatia
2–1GAFFER53%
Market54%
no edge · pass
Jun 270–0Draw
0–0GAFFER27%
Market24%
Draw @ 0.25 · edge +2.4%
+$300
Jun 273–1DR Congo
3–1GAFFER37%
Market58%
Draw @ 0.25 · edge +11.8%
−$100
Jun 271–3Argentina
1–3GAFFER87%
Market86%
no edge · pass
Jun 273–3Draw
3–3GAFFER29%
Market46%
Austria @ 0.28 · edge +9.0%
−$100
Jun 280–1R32Canada adv.
0–1GAFFER66%
Market72%
South Africa @ 0.29 · edge +5.1%
−$100
Jun 292–1R32Brazil adv.
2–1GAFFER67%
Market74%
Japan @ 0.27 · edge +6.3%
−$100
Jun 291–1R32Paraguay adv. (pens)
1–1GAFFER27%
Market14%
Paraguay @ 0.14 · edge +12.6%
+$614
Jun 291–1R32Morocco adv. (pens)
1–1GAFFER46%
Market42%
Morocco @ 0.42 · edge +3.5%
+$138
Jun 301–2R32Norway adv.
1–2GAFFER56%
Market65%
Ivory Coast @ 0.36 · edge +8.0%
−$100
Jun 303–0R32France adv.
3–0GAFFER76%
Market89%
Sweden @ 0.12 · edge +12.2%
−$100
Jun 302–0R32Mexico adv.
2–0GAFFER49%
Market64%
Ecuador @ 0.37 · edge +14.2%
−$100
Jul 12–1R32England adv.
2–1GAFFER77%
Market88%
DR Congo @ 0.13 · edge +10.3%
−$100
Jul 13–2R32Belgium adv.
3–2GAFFER58%
Market67%
Senegal @ 0.34 · edge +8.2%
−$100
Jul 12–0R32United States adv.
2–0GAFFER73%
Market84%
Bosnia and Herzegovina @ 0.17 · edge +10.5%
−$100
Jul 23–0R32Spain adv.
3–0GAFFER74%
Market88%
Austria @ 0.12 · edge +14.2%
−$100
Jul 22–1R32Portugal adv.
2–1GAFFER65%
Market73%
Croatia @ 0.28 · edge +6.9%
−$100
Jul 22–0R32Switzerland adv.
2–0GAFFER56%
Market67%
Algeria @ 0.34 · edge +9.6%
−$100
Jul 31–1R32Egypt adv. (pens)
1–1GAFFER51%
Market61%
Australia @ 0.40 · edge +9.1%
−$100
Jul 33–2R32Argentina adv.
3–2GAFFER86%
Market93%
Cape Verde @ 0.08 · edge +5.9%
−$100
Jul 31–0R32Colombia adv.
1–0GAFFER71%
Market81%
Ghana @ 0.20 · edge +9.6%
−$100
Jul 60–1R16Spain adv.
0–1GAFFER57%
Market66%
Portugal @ 0.35 · edge +7.6%
−$100
Jul 61–4R16Belgium adv.
1–4GAFFER59%
Market47%
Belgium @ 0.47 · edge +11.8%
+$113
Jul 73–2R16Argentina adv.
3–2GAFFER76%
Market86%
Egypt @ 0.15 · edge +9.1%
−$100
Jul 70–0R16Switzerland adv. (pens)
0–0GAFFER46%
Market39%
Switzerland @ 0.40 · edge +5.9%
+$150
Jul 92–0QFFrance adv.
2–0GAFFER61%
Market78%
Morocco @ 0.23 · edge +15.8%
−$100
Jul 102–1QFSpain adv.
2–1GAFFER65%
Market74%
Belgium @ 0.27 · edge +8.5%
−$100
Jul 111–2QFEngland adv.
1–2GAFFER65%
Market68%
Norway @ 0.33 · edge +2.1%
−$100
Jul 113–1QFArgentina adv.
3–1GAFFER66%
Market76%
Switzerland @ 0.25 · edge +8.9%
−$100
Jul 140–2SFSpain adv.
0–2GAFFER55%
Market43%
Spain @ 0.44 · edge +11.5%
+$127
69 of 102 played games scored (44 group, 25 knockout) · 32 had no logged pre-match prediction (games before we started snapshotting) · 1 had no Kalshi market. Knockout ties are graded on Kalshi's 2-way “advances” market (extra time & penalties included); group games on the 3-way moneyline. Bets are placed at the single largest GAFFER edge per game when it clears 2%, entered at Kalshi's pre-match ask. Accuracy compares de-vigged probabilities; P&L uses the raw, vig-inclusive ask — the honest cost of actually trading.