SCAN AND THE PSE TRADITION

The development of a series of instruments that has so far culminated in SCAN version 2.0 began in the late 1950s because of the need for be tter tools for clinical measurement (including categorization and diag nosis). The basic principles of the PSE had long been decided by the t ime of first publication in 1974 and have remained the same since. Bas ed on the glossary of differential definitions, the aim is to provide comprehensive, accurate and technically specifiable means of describin g and classifying clinical phenomena in order to make comparisons. Ins ofar as it fulfils this aim, SCAN can be used to enhance clinical work and education and advance knowledge through its use in biomedical, ep idemiological and psychosocial research.