Overview of DeCS's tree structure
DeCS follows the tradition of the classification systems and their respective subject heading lists which have been transformed into specialized vocabularies without, however, changing the structures of the classification systems from which they originated. Its tree structure is well-grounded in the division of knowledge in decimal classes and subclasses respecting their conceptual and semantic relationships, and its terms are presented in a hybrid structure of pre- and post-coordination. See also the qualifier hierarchical tree.
DeCS vocabulary concepts are distributed as follows (2019 version):
30.0% refer to chemical compounds and drugs (D category), both exogenous and endogenous;
23.1% of the total are anatomical terms (A category), organisms (B category) and phenomena and processes (G category);
14.2% of the total refer to diseases (C category);
Categories such as techniques and equipment (E category), allied sciences (F, H, I, J, K, L, M and N categories), publication characteristics (V category) and geographic locations (Z category) altogether represent 22.6%;
Public Health (SP category) is represented by 11.1%, Homeopathy (HP category) by 5.7%, Health Surveillance (VS category) by 2.4%, and Science and Health (SH category) by 0.7%. These last four categories were especially developed to better represent the literature generated in the countries of the region.
Updated: June 2019