
Good explanation. To elaborate though, usually the dog has to be over a year old before the hip x-ray's can be done.
The measurements taken are given a number of points. 0 - 0 is PERFECT! However that is rare. Each hip joint is scored out of 53 points these points are then added together to make a total score. So if the left hip scores 2 points and the right hip scores 3 the total is 5, (that is 5 out of a possible total of 106).
Every breed has an average or mean score. In flatcoats it is currently 9. The score average can be obtained from your vet or the BVA (the BVA publish a list every couple of years which gives the average score for every breed). It is worth knowing that the police and military take dogs with a hip score of up to 20 points. You can write to the BVA for a booklet which explains with diagrams hip scoring. British Veterinary Association, 7, Mansfield street, London.
I have found with my dogs I get a better score if I wait until they are at least two years old before hip scoring x-rays are done. If you have a bitch, try to get her scored midway between seasons as the season will affect her score.
Equally a bad x-ray plate can affect the score. So the vet must try to send a plate which is neither too dark nor too light, (thin). The dog must be positioned just right otherwise this can increase the number of points gained as well.