Are Small Effects for Back Pain Interventions Really Surprising?

There is reasonably strong evidence that some physical therapy interventions are effective (compared to minimal or no intervention) for patients with low back pain (LBP); however, the effect sizes are typically small. Many clinicians argue that this evidence is at odds with their daily clinical experience. There are several reasons that likely contribute to small effects in clinical trials of LBP and other musculoskeletal conditions. In this Viewpoint, the authors look at which of these reasons are beyond our control as clinicians and simply need to be acknowledged and understood, and which may provide insights into improving the design of future clinical trials of LBP and ultimately delivering better care to our patients. J Orthop Sports Phys Ther 2016;46(5):317-319. doi:10.2519/jospt.2016.0604.