What a hip score actually tells you

A breeder tells you the sire scored 8. You nod, because 8 sounds low, and low sounds good. What you have not been told, and what the certificate does not say on its own, is 8 out of what, compared to whom, and whether 8 is remarkable or completely unremarkable for that breed. A hip score is not a grade. It is a measurement, and a measurement is only informative next to another one.

What is actually being measured

The scheme is run jointly by the British Veterinary Association and the Royal Kennel Club, and it has been going since 1965, which makes it one of the oldest health screens in British dog breeding. A vet takes an X-ray of the dog under anaesthetic or heavy sedation, and the film is read independently by two of a panel of ten scrutineers — vets with advanced qualifications in radiology or orthopaedics — who score each hip on nine separate points and then agree a total between them.

Each hip is scored from 0 to 53. The two sides are added together, giving a range of 0 to 106 for the dog. Lower is better, and 0 is the lowest score a hip can receive.

The nine points split into two groups. The first three, called the primary changes, look at how well the ball of the femur actually sits in the socket — the raw conformation of the joint, independent of the dog's age. The remaining six, the secondary changes, look for the arthritic wear that develops as a badly-fitting joint grinds against itself over time. A young dog can have poor primary scores with almost no secondary change yet visible; an older dog with borderline conformation may have accumulated secondary scores that a two-year-old of the same true joint quality would not yet show. This is one reason the scheme requires a dog to be at least a year old before submission, and why breed practice for the more dysplasia-prone breeds is often to wait well past that minimum.

The number means nothing without the median

Here is the part the certificate does not put in front of you: a total score is compared against the current breed median, not against zero and not against some universal idea of a sound hip. The median is recalculated from the previous five years of submissions for that breed, published annually, and it moves. A score of 8 in a breed whose median sits at 4 is a poor result for that breed. The same 8 in a breed whose median sits at 18 is a good one. BVA's own guidance is direct about this: breed only from dogs scoring below, or close to, their breed's published median, and treat the raw total as meaningless until you have looked that median up.

This is why a listing, a stud advert, or a breeder's own website that states a score without naming the breed median is giving you half a fact. The other half — what is the current median for this breed, this year — takes about a minute to find on BVA's published breed-specific statistics, and it changes the meaning of everything else on the page.

Where they exist, Estimated Breeding Values go a step further than the median comparison. An EBV uses the scores of a dog's relatives as well as its own, which corrects for the fact that a single X-ray is one data point on a condition with a strong genetic component but a real environmental one too — growth rate, weight as a puppy, exercise before the growth plates close. BVA recommends using the EBV over the raw score wherever a breed has one calculated.

What a good score does not guarantee, and what a poor one does not condemn

Hip dysplasia is described by BVA as multifactorial, and that word is doing real work. Two parents with excellent scores can still produce a puppy with poor hips, because conformation, growth rate, and joint laxity interact in ways a single radiograph of the parent does not fully capture. Breeding from low-scoring stock reduces the incidence of the condition across a breed over generations. It does not, and cannot, eliminate it in any individual litter.

The reverse also holds. A dog with a score above the median is not necessarily going to develop clinical dysplasia, and plenty of moderately-scored dogs live full, comfortable, unremarkable lives. What a poor score tells a breeder is that this individual's genetic contribution to the breed's hip health is working against the average, which is a breeding decision, not a diagnosis of suffering.

What to actually ask for

Before you commit to a puppy from health-tested parents, the useful questions are narrower than "were the hips scored":

• What was the actual total, for each parent, and on what date.
• What is the current breed median for that breed, and how does each parent's score sit against it.
• If an EBV exists for the breed, what is it, rather than the raw score alone.
• Was the result published on the Royal Kennel Club's Health Test Results Finder — a published result is independently checkable; a score only quoted verbally or on a certificate you cannot verify is not.

None of this requires expertise. It requires the breed median in one hand and the certificate in the other, and five minutes to hold them up against each other before you decide what a number like 8 actually means.

Why we ask for the comparison, not just the certificate

We have written before about the gap between having a test done and reading what it says — see how to read a health-testing certificate and, more generally, what good health testing actually looks like. Hip scoring is the clearest example we have of a test whose number is close to unreadable in isolation. A listing that shows the score without the breed median it should be read against is not lying, but it is relying on the fact that most buyers will not go and check. That is the exact gap we think a listing should close rather than lean on, which is the same principle behind what verified breeder actually means: show the record, and show what the record has to be measured against, rather than trusting the number to speak for itself.

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Sources

• BVA Hip Dysplasia Scheme for dogs
• Understanding the results — CHS online submission portal
• Hip breed-specific statistics 2024 — BVA
• Interpretation and use of BVA/KC hip scores in dogs — Ruth Dennis, In Practice (2012)
• Royal Kennel Club Health Test Results Finder

— Rene