Brittany, just because someone posts something on the web ie the above mentioned link, does not mean that it is correct. The gradings listed there do not correspond with how the SV actually rates hips. Rather shocking that the OFA lists on their own hips grading page (http://www.offa.org/hipgrade.html - bottom of page) that they consider a-normal to cover all passing OFA grades from Excellent to Fair. From experience, we know that that is not the case.
HDa3, or HD noch zugelassen does not mean that the dog is dysplastic. HDa3 means that it is still acceptable for breeding. HDa4 is the SV rating for mild HD, and HDa5 is the SV rating for severe HD. Neither does a2 too mean "suspicious" for HD, it means that the hips are nearly normal, but just not quite perfect. Few things are perfect in nature. You also have to consider the WHOLE dog in breeding, not just parts of it. Breeding is not like baking a cake where you take a pinch of good hips, a smidgen of good angulation, an ounce of nice head, a pound of good topline, a few drops of extra colour, mix if really fast for good movement and voila you got yourself a good dog. Sigh.
No HD certification is fool proof. PennHip is touted to the most correct, but few vets are certified and fewer breeders use it for one simple reason: EVERY dog that goes in for a PennHip gets a score, even if the hips do not look good. So if a breeder does not want his lines "tarnished" with a possible bad hip result, he will most likely avoid PennHip. With the a-stamp and OFA breeders have the option NOT to send in the x-ray, thus falsifying all the existing statistics. Since far more GSD have been screened via SV-stamp, the SV stats are still more representative than the OFA stats will ever be.
The way dogs are x-rayed is also slightly different for each method of certification, hence different results when a dog gets re-certified elsewhere. In Germany the dog gets put into a device that postitions the dog and it fully knocked out during the x-ray. How a vet takes the x-ray will influence the result too. If the dog was put under will incluence the result. Age, possible injuries, physical trauma and stress, diet, all that will influence how the hips look from one x-ray to the next.
Many owners and breeders have had experiences, or heard of other people's experiences where a dog came back with a result that was different than expected. In both directions. We recently had a female the vet predicted would get a1, she came back with a3. And that is not a first. Another female the vet said would not even get an a3. Turns out the positioning was aweful. A new x-ray at a different vet and this one came back, as the new vet had predicted, with a2. I still have the first "off" x-ray on file. Email me if you want to see it and see for yourself how "bad" an x-ray has to look in order for a vet to consider it not even worthy of a3. With the OFA you can rather easily contest how a dog has been certified, re-screend the dog, and often the new x-rays come back with a different score than the original one. So how precise is this whole process really! With the SV going against the a-stamp decision is nearly impossible, so few people try. The trick is to get it right before sending it in, like with the female that ended up with an a2. So how precise is the process really!