How the Breed Health Score works
Every breed gets a single 0 to 100 score (higher is healthier), combining three components:
- Longevity (65%): median lifespan mapped from 8 years (score 0) to 15 years (score 100). From McMillan, K.M. et al. (2024) "Longevity of companion dog breeds", Scientific Reports (584,734 UK dogs). Data CC-BY 4.0.
- Conformation (20%): deductions for flat-faced (brachycephalic) and giant conformation risk.
- Hereditary burden (15%): deductions per known condition, weighted more heavily for life-threatening ones (cancer, heart disease, BOAS, bloat, IVDD). This is a count of reported conditions, so it is influenced by how well-studied a breed is: better-documented breeds tend to list more. That is why it carries the least weight, while longevity (real, cited data) carries the most.
How the weights are set. The three weightings are our own editorial choice, published in full so you can see exactly how each score is built. The data underneath is real, peer-reviewed and cited (median lifespan from 584,734 dogs).
Data sources. Median lifespan: McMillan et al. 2024 (CC-BY 4.0). Conditions and conformation: RVC VetCompass, AKC, PDSA, UK Kennel Club (indicative). Photos: Pexels. Machine-readable: /api/breeds.json.