Polythematic Structured Subject Heading System

Polythematic Structured Subject Heading System (abbreviated as PSH from the Czech Polytematický Strukturovaný Heslář) is a bilingual Czech–English controlled vocabulary of subject headings developed and maintained by the National Technical Library (the former State Technical Library) in Prague.

Starting 1997,[1] PSH has been distributed to other libraries and companies, originally as a commercial, paid product; since 2009[2] for free.

In 2000, the State Technical Library received a grant from the Ministry of Culture to translate PSH into English.

[3] The vast majority of new subject headings is suggested and approved by the indexing experts from the National Technical Library.

The main decisions about the development and the future of PSH are done by the Committee for Coordination of Polythematic Structured Subject Heading System.

The Committee meets once a year in the National Technical Library; in the meantime, the members communicate using an electronic mailing list.

Equivalence relations link subject headings with their nonpreferred versions (e.g. electrocardiography and ECG).

This enables users to recognize affiliation of subject headings from lower levels to the thematic sections.

It is possible to display tags from PSH (metadata snippets – Dublin Core and CommonTag), which can be embedded in an HTML document to provide its semantic description in a machine-readable way.

Within the data analysis, users queries are divided into seven categories that contain the title of the document, person, subject, action, institution, geographical terms and others.