AFL Insights
Nathan Williamson

Umpire profile

Nathan Williamson

No. 22 Heritage 436 Active Last officiated 16 Jul 2026

Lean, Victorian bias and upset history for 2022-2026.

Upset likelihood

33.0%

Eligible underdog win rate

Matches 112 · Baseline 28.6% · +4.5 pts

Victorian bias

+2.6 pts

Victorian side vs non-Victorian opponent

Matches 90 · Free-kick diff +0.7

Significant upsets

5

Only 60%+ favourites with 60+ upset scores count.

2022-2026

Club ladder

All teams ranked by lean

Lean is residual margin versus the closing line. Free-kick diff is context only.

# Club Matches Lean Free-kick diff
1
Brisbane Lions
26 +6.4 pts +0.3
2
GWS
28 +5.8 pts -2.2
3
North Melbourne
17 +5.3 pts +1.3
4
Geelong
31 +5.3 pts -1.0
5
St Kilda
16 +4.4 pts -0.5
6
Carlton
32 +4.0 pts +2.1
7
Hawthorn
19 +2.2 pts -0.7
8
Port Adelaide
23 +2.2 pts -0.4
9
Collingwood
29 +1.5 pts +0.4
10
Fremantle
32 -0.8 pts -0.3
11
Melbourne
39 -1.5 pts -0.3
12
Western Bulldogs
32 -1.7 pts +1.1
13
Richmond
20 -2.0 pts -1.0
14
Essendon
20 -3.7 pts -0.7
15
Adelaide
29 -5.5 pts +1.1
16
Gold Coast
25 -5.6 pts -1.5
17
Sydney
26 -7.1 pts +0.7
18
West Coast
24 -8.0 pts +0.9

Officiated shocks

Top significant upsets

Only 60+ upset scores with a 60%+ favourite are shown, so fewer than five is normal.

Geelong 9.10 64 def. by Fremantle 10.11 71 91

Round 20 · 29 Jul 2023 · Kardinia Park

10.50 odds · 94% favourite · 7-pt win · 48.5-pt dog

West Coast 16.9 105 def. Fremantle 10.8 68 90

Round 6 · 20 Apr 2024 · Optus Stadium

6.00 odds · 87% favourite · 37-pt win · 33.5-pt dog

Melbourne 7.7 49 def. by Fremantle 22.9 141 78

Round 12 · 2 Jun 2024 · Traeger Park

2.68 odds · 67% favourite · 92-pt win · 8.5-pt dog

Gold Coast 11.10 76 def. by GWS 17.9 111 77

Round 23 · 16 Aug 2025 · Carrara

3.30 odds · 74% favourite · 35-pt win · 18.5-pt dog

Hawthorn 14.6 90 def. by Melbourne 19.11 125 75

Round 17 · 4 Jul 2026 · UTAS Stadium

3.06 odds · 72% favourite · 35-pt win · 17.5-pt dog