ABSTRACT
Thus a manualised approach provides an easy focus for training and supervision. It is also a reference point in determining whether appropriate therapy has been conducted.
One of Beck’s earliest publications focused on making psychiatric diagnoses more reliable (Beck et al. 1962). Beck and his colleagues found that the level of agreement about whether a person had a particular disorder varied between 32% and 54%. This made researching the effectiveness of treatments near impossible because a particular client might be described by one person as suffering from depression but another assessor would give a quite different label. To help ensure good levels of agreement, Beck drew attention to the importance of minimising (a) information variance – the range of information considered important in making a particular diagnosis and (b) criteria variance – the information needed to establish the presence or absence of a particular symptom. This led to the publication of agreed criteria for each disorder, currently embodied in DSM-IV-TR (American Psychiatric Association 2000) and published guidance on the thresholds needed to determine whether a particular symptom can be regarded as present (SCID, First et al.
