The validity of the studies that the American Board of Internal Medicine cites to support these arguments has been questioned, because the authors of these studies are individuals who are employed by, or have previously been employed by, the American Board of Medical Specialties or its related bodies (see Hawkins, Richard E.).[14] In addition, there appears to be a tightly-knit, self-credentialed "patient safety/medical quality" industry developing in the United States, from which the authors of many of the studies supporting maintenance of certification have emerged.[15]