Jump up ^ The accreditation criteria and the structure of the accreditation system were based on those described in Yeates, Lindsay B., A Set of Competency and Proficiency Standards for Australian Professional Clinical Hypnotherapists: A Descriptive Guide to the Australian Hypnotherapists' Association Accreditation System, Australian Hypnotherapists' Association, (Sydney), 1996. ISBN 0-646-27250-0  Archived 2009-09-12 at the Wayback Machine.
Braid made a rough distinction between different stages of hypnosis, which he termed the first and second conscious stage of hypnotism; he later replaced this with a distinction between "sub-hypnotic", "full hypnotic", and "hypnotic coma" stages. Jean-Martin Charcot made a similar distinction between stages which he named somnambulism, lethargy, and catalepsy. However, Ambroise-Auguste Liébeault and Hippolyte Bernheim introduced more complex hypnotic "depth" scales based on a combination of behavioural, physiological, and subjective responses, some of which were due to direct suggestion and some of which were not. In the first few decades of the 20th century, these early clinical "depth" scales were superseded by more sophisticated "hypnotic susceptibility" scales based on experimental research. The most influential were the Davis–Husband and Friedlander–Sarbin scales developed in the 1930s. André Weitzenhoffer and Ernest R. Hilgard developed the Stanford Scale of Hypnotic Susceptibility in 1959, consisting of 12 suggestion test items following a standardised hypnotic eye-fixation induction script, and this has become one of the most widely referenced research tools in the field of hypnosis. Soon after, in 1962, Ronald Shor and Emily Carota Orne developed a similar group scale called the Harvard Group Scale of Hypnotic Susceptibility (HGSHS).
When James Braid first described hypnotism, he did not use the term "suggestion" but referred instead to the act of focusing the conscious mind of the subject upon a single dominant idea. Braid's main therapeutic strategy involved stimulating or reducing physiological functioning in different regions of the body. In his later works, however, Braid placed increasing emphasis upon the use of a variety of different verbal and non-verbal forms of suggestion, including the use of "waking suggestion" and self-hypnosis. Subsequently, Hippolyte Bernheim shifted the emphasis from the physical state of hypnosis on to the psychological process of verbal suggestion: