Three aims in one

The aim of SCAN can be stated very simply, in one sentence. It is to provide comprehensive, accurate and technically specifiable means of describing and classifying clinical phenomena, in order to make comparisons. Making comparisons is at the heart of all clinical, educational and scientific activities. Even making a single assessment using SCAN provides the opportunity to make comparisons with other patients known to the same clinician. Every interview and every prescription can be seen as a clinical experiment.

The first, clinical, aim is to promote high-quality clinical observation. PSE-10 is designed to allow a comparison of the respondent's experiences and behaviour against the examiner's Glossary-defined concepts, by a process of controlled clinical cross-examination. The resulting symptom profiles, scores and rule-based categories of disorder, can be compared with each other wherever in the world they are produced, and used for clinical audit, needs assessment and monitoring of progress of individual respondents.

The second aim, educational and developmental, is to improve clinical concepts by teaching a common clinical language. This makes it feasible to compare, and learn from, the usage of different clinical schools. It is not necessary to agree with a common standard of reference to appreciate its value as a basis for communication and comparison. Different clinical schools of thought do exist and are taught. Comparison between them by means of a common standard of reference provides a basis for informed development.

The third, scientific, aim is to accelerate the accumulation of knowledge. Using standard technical procedures in research projects makes the results more precise and comparable, thus leading to more rapid agreement on useful theoretical lines for further research. This is true of all types of scientific research – biological, epidemiological and psychosocial.

The three aims together facilitate the accumulation of knowledge for clinical purposes of all kinds, including primary, secondary and tertiary prevention and high quality health-service management and planning. SCAN itself will benefit, both from the comparisons it has supported and from the results of the work it has facilitated. New item-concepts will be added and old ones improved. But modifications should be made in carefully designed stages, following periods of experience long enough to provide a substantial basis for change. This is how SCAN has developed so far.