Pennhip testing is not as commonly done as OFA hip testing. OFA grading is more subjective and is looking at the hips anatomical abnormalities to determine hip health from a single image, based off human judgement and opinion. Pennhip is looking at 3 different images of the hip to determine hip joint laxity by measuring for the distraction index (DI). This number is then compared to the breed average to place it at a risk level.