The Library of Congress created their children's subject headings, first named that Annotated Card Program, in 1965 in response to requests from librarians for children and youth (Intner & Weihs, 2015).
The materials with children's subject headings are treated a little different from the regular LC subject headings in regards to descriptive and subject cataloging. These are some of the ways in which they differ from the usual LC subject headings:
Descriptive Cataloging includes summaries-this can be helpful for adults, as well.
There are no subdivisions that indicate age-level (i.e. JUVENILE FICTION)
The subject headings have been modified in a number of ways, such as added to, or simplified in order to make them more accesible to children.
The modification of subdivision practice was done in order to assign subject headings to individual works of fiction and biographies in fields that LC subject headings had not established.
These subject headings can be implemeted in a number of ways. If a library maintains separate catalogs for adults and children, both adult and children's cataloging can be used. If they only have access to one catalog, it is possible to use the headings for only the specific audience they feel would benefit from it.
Resources for LC Children's Subject Headings
The Library of Congress home page for the LC Children's Subject Headings. It includes some background information, along with frequently asked questions, and more.