The average MDQ change score for patients with low back pain treated during the observation period will be reported. Additionally, a risk-adjusted MDQ change difference score will be calculated by subtracting the predicted MDQ change score from the average MDQ change score for each patient, then average the adjusted scores for each physical therapist or physical therapy group. The risk adjustment will be calculated using generalized linear modelling adjusting for: baseline MDQ score, baseline pain score, age, sex, smoking, comorbidities, payer, and symptom duration (time from surgery or injury to baseline physical therapy visit). These measures will serve as a physical or occupational therapy performance measure at the eligible physical or occupational therapist or physical or occupational therapy group level. Rate 1: Average MDQ Change Score, Rate 2: Risk-adjusted Average MDQ Change Score for each of the following: 1) Overall (all eligible patients), 2) non-surgical patients, 3 surgical patients.