Glossary
Plain-English definitions of the terms used across the site and in the Breed Health Score.
- Breed Health Score
- Our single 0 to 100 score for a breed (higher is healthier), combining longevity (65%), conformation risk (20%) and hereditary disease burden (15%). See the methodology.
- Longevity
- How long the breed typically lives. Based on median lifespan from a peer-reviewed study of 584,734 UK dogs (McMillan 2024). A higher score means longer-lived.
- Median lifespan
- The midpoint age at death for the breed in the study: half of dogs lived longer, half shorter. It is a population figure, not a prediction for any one dog.
- Conformation
- Health risk from body shape. We deduct points for flat-faced (brachycephalic) breeds and for giant size, which carry known breathing, joint and heart risks.
- Brachycephalic (flat-faced)
- Flat-faced skull shape (for example Pug or Bulldog). Linked to breathing difficulty (BOAS), eye and skin problems.
- BOAS
- Brachycephalic Obstructive Airway Syndrome: the breathing difficulty common in flat-faced breeds, caused by narrowed airways.
- Giant breed
- The largest size category (for example Great Dane, Mastiff). Giant breeds tend to live shorter lives and carry higher joint, heart and bloat risk.
- Hereditary disease burden
- The load of known hereditary conditions: a count of reported conditions weighted for severity. It carries the least weight because better-studied breeds tend to have more conditions on record.
- Grade
- A simple A to E band based on the overall 0 to 100 score. A is healthiest, E is most at risk.
- Provisional score
- A score shown when we do not yet have condition data for a breed, so it is based on longevity and conformation only.
- CC-BY
- A Creative Commons licence that lets us reuse and publish the underlying lifespan data as long as we credit the source.
See how the components fit together on the methodology page.