Hamilton’s hesitancy to publish precise details of rating procedures stimulated others to attempt this. A Structured Interview Guide developed by Williams, the SIGH-D, suggests open-ended questions for each item and indicates how to translate replies into ratings; use of the guide improved reliability of ratings (45, Table 2). The SIGH-D is presented in an appendix to Williams’s article (45, pp57–63). Potts et al. developed a Structured Interview Guide for use in the Medical Outcomes Study, the SIHDRS, which can be used by lay interviewers (46). The SI-HDRS has an alpha reliability of 0.82 (46, p344). Rehm and O’Hara also provided guidelines for standardizing the ratings (11).