Medical devices are cleared for marketing approval through the Food and Drug Administration (FDA). Unique statutory requirements, such as the "least burdensome mandate," have allowed the FDA to employ non-concurrent controls in its evaluation of prospective therapies. The use of Objective Performance Criteria and Goals (OPC and OPG) for the premarket evaluation of cardiovascular devices has become established as an alternative to randomized, controlled trials (RCTs). These single-armed comparisons may facilitate rapid entry of novel devices to the market. Unlike RCTs, they do not establish superiority or non-inferiority of the examined therapy, and study populations must be carefully inspected to ensure validity of comparisons to historical controls.