Okay, so you know how sometimes you get sick and your mom or dad takes your temperature with a thermometer? And you know how the higher the number on the thermometer, the more sick you are?
Well, doctors and scientists came up with something called the Horsfall-Barratt scale to see how bad someone's kidney stones are. Kidney stones are little hard pieces that form in your kidneys and can make it hurt a lot when you go pee.
The Horsfall-Barratt scale looks at the shape and size of the kidney stones under a special microscope to see how hard they are to get rid of. Just like how a bigger number on the thermometer means a worse sickness, a higher number on the Horsfall-Barratt scale means the kidney stones are harder to deal with.
Doctors use this scale to figure out the best way to help people with kidney stones feel better.