Curves generally progress at a slower rate when the child is younger and when the curve is smaller. Curves progress at their fastest rate during (and just after) the adolescent growth spurt and then slow down as the child reaches skeletal maturity. However the progression rate also varies from one person to another and can be slower or faster than usual or faster than average. If we have more than one ‘out-of-brace’ x-ray, then we can use the change in Cobb size to estimate whether the scoliosis can be considered a slow, average or fast progression. This calculator is therefore used to give you an estimate of progression rate and expected outcome with no treatment.  The resulting Progression Rate determination can then be used to provide a more accurate prediction in the Outcome Prediction calculator.