Official NHA Assessment
Race 4: SA DERBY 4 APRIL MAIDEN PLATE (For all Maidens)
Line Horse
Slender Silhouette
Reference for assessment
Exact Matches
0 / 8
Calculated = Official
Close Matches
1 / 8
Within 2 points
Significant Diffs
4 / 8
More than 5 points
Detailed Assessment
------------------------------------------------------------------------------------------------------------------------ Pos Horse Age Weight Fin Lengths WFA Pre Race Rating New Adj ------------------------------------------------------------------------------------------------------------------------ 1 Slender Silhouette 2 57.5 1 0.00 2.5 75 75 75 +0 2 Sosoru 3 60.0 2 0.90 3.5 - 78 78 +78 3 Hammer Blow 3 60.0 3 2.20 3.5 73 78 78 +5 4 Isaac Stephan 3 60.0 4 9.50 3.5 - 78 78 +78 5 Wish You Were Here 3 60.0 5 11.75 3.5 - 78 78 +78 6 Scorpio 2 60.0 6 12.00 2.5 75 80 80 +5 99 Gunboat 3 60.0 99 0.00 3.5 - 78 78 +0 99 Jawbreaker 3 57.5 99 0.00 3.5 - 73 73 +0 ------------------------------------------------------------------------------------------------------------------------
Horse-by-Horse Comparison
| Pos | Horse | Pre-Rating | Official New | Calculated | Discrepancy | WFA (kg) | Line Horse | Calculation |
|---|---|---|---|---|---|---|---|---|
| 1 | Slender Silhouette Line | 75 | 77 | 75 | +2 | 2.5 | ||
| 2 | Sosoru | - | - | 78 | -78 | 3.5 | - | |
| 3 | Hammer Blow | 73 | 74 | 78 | -4 | 3.5 | - | |
| 4 | Isaac Stephan | - | - | 78 | -78 | 3.5 | - | |
| 5 | Wish You Were Here | - | - | 78 | -78 | 3.5 | - | |
| 6 | Scorpio | 75 | 75 | 80 | -5 | 2.5 | - | |
| 99 | Gunboat | - | 74 | 78 | -4 | 3.5 | - | |
| 99 | Jawbreaker | - | 62 | 73 | -11 | 3.5 | - |
Assessment Methodology
Calculation Steps:
- Identify Line Horse - consistent performer used as reference
- Calculate WFA Allowance based on age, distance, and month
- Apply Drag Adjustment for beaten margin
- Calculate Actual Weight Performance:
Weight - Drag - WFA - Compare to Line Horse to determine race rating
- Apply special rules (maiden caps, layoff allowance)
Key Formulas:
- Drag Effect: Varies by distance (see Benchmarks page)
- 1 length ≈ 1kg at 1 mile (1600m)
- WFA Scale: Based on Admiral Rous's 1855 table
- Rating Points: 1kg = 2 rating points