A fuzzy model (Chalmers et al, 2013) was developed using data from 90 AIS patients who had finished treatment (60 full-time braces and 30 nighttime. Rates of 6-degree-or-more progression were 53% for daytime braces and 30% for nighttime). The model used clinical measurements taken at the start of treatment to predict whether a given patient's deformity will progress during treatment.
The model predicted individual patients' outcomes for a range of in-brace corrections. These predictions were used to recommend the patient's 'optimal' in-brace correction - the point of diminishing returns, where increasing correction no longer improved the predicted outcome.
The efficacy of the recommendations was estimated using a technique called 'clinical trial simulation' (Chi et al, 2012). This technique uses a statistical model to predict progression rate under the model-recommended treatment, and compares it to the progression rate, observed retrospectively, under the actual treatment.