The main goal of this research project is to conduct a comparative effectiveness research study involving existing data in the PCORnet Common Data Model to provide accurate estimates of the 1-, 3-, and 5-year benefits and risks of the three most common bariatric procedures - Roux-en-y gastric bypass, adjustable gastric banding, and sleeve gastrectomy - with a focus on outcomes that are important to adults and adolescents with severe obesity: 1) changes in weight, 2) rates of remission and relapse of diabetes, and 3) major adverse events.