Chainladder Modeling
Compare pooled and feature-segmented chainladder estimates using the synthetic triangles generated from the claims data.
Claims Modeled
1,247
Chainladder applied with and without segmentation
Pooled chainladder
Ultimate: $8,432,100
IBNR: $2,156,800
Severity-segmented
Ultimate: $8,124,500
IBNR: $1,849,200
Ground truth (synthetic)
Ultimate: $8,021,300
IBNR: $1,746,000
Segmentation effect
72.3% closer to true ultimate
Severity segmentation reduces ultimate estimate error by 72.3%, showing significant heterogeneity in development patterns across severity classes.
Claim coverage
1,247
Synthetic triangles built from all claims, segmented by severity
Method comparison
| Method | Ultimate | IBNR | IBNR Error vs. True |
|---|---|---|---|
| Pooled Chainladder | $8,432,100 | $2,156,800 | 23.5% |
| Severity-Segmented | $8,124,500 | $1,849,200 | 5.9% |
| Ground Truth (Synthetic) | $8,021,300 | $1,746,000 | 0.0% |
Severity breakdown
Segmented chainladder results
| Segment | Claims | Latest Paid | Ultimate | IBNR | Share of segmented IBNR |
|---|---|---|---|---|---|
| major | 87 | $3,421,000 | $4,236,800 | $815,800 | 44.1% |
| moderate | 342 | $2,154,200 | $2,876,300 | $722,100 | 39.0% |
| minor | 818 | $700,100 | $1,011,400 | $311,300 | 16.8% |
| Total | 1,247 | $6,275,300 | $8,124,500 | $1,849,200 | 100% |
major
Claims with initial severity >$50,000. Slowest development, highest reserves.
moderate
Claims with initial severity $10,000-$50,000. Standard development pattern.
minor
Claims with initial severity <$10,000. Fast settlement, minimal tail.