science

Library of Congress Subject Headings

Library of Congress Subject Headings is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Library of Congress Subject Headings rather than just read about it. In short: The Library of Congress Subject Headings (LCSH) comprise a thesaurus (in the information science sense, a controlled vocabulary) of subject headings, maintained by the United States Library of Congress, for use in bibliographic records. LC Subject Headings are an integral part of bibliographic control, which is the function by which libraries collect, organize, and disseminate documents.

Key takeaways

Library of Congress Subject Headings belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Library of Congress Subject Headings to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Library of Congress Subject Headings from memory before moving on to harder problems.

Reference excerpt

The Library of Congress Subject Headings (LCSH) comprise a thesaurus (in the information science sense, a controlled vocabulary) of subject headings, maintained by the United States Library of Congress, for use in bibliographic records. LC Subject Headings are an integral part of bibliographic control, which is the function by which libraries collect, organize, and disseminate documents. It was first published in 1898, a year after the publication of Library of Congress Classification (1897). The last print edition was published in 2016. Access to the continuously revised vocabulary is now available via subscription and free services. Subject headings are normally applied to every item within a library's collection and facilitate a user's access to items in the catalog that pertain to similar subject matter, in order to save time finding items of related subject matter. Only searching for items by 'title' or other descriptive fields, such as 'author' or 'publisher', would take more time and potentially miss locating many items because of the ineffective and inefficient search capability.

An art and a science The use of subject headings is a human and intellectual endeavor, by which trained professionals apply topic descriptions to items in their collections. Without a uniform standard, each library might choose to categorize the subject matter of their items differently. The widespread use and acceptance of the Library of Congress Subject Headings facilitates the uniform access to and retrieval of items in libraries across the world; users can use the same search strategy and LCSH thesaurus, if the correct headings have been applied to the item by the library. Some LCSH decisions are achieved by extensive debate and even controversy in the library community. LCSH is the world's most widely used subject vocabulary. Despite LCSH's wide-ranging and comprehensive scope, libraries that deal with more specific types of collections or user communities may use other vocabularies; for example, many medical libraries in the United States use the National Library of Medicine's Medical Subject Headings (MeSH).

Policy issues Historically, given the complicated nature of the United States, its various ethnic groups, and changing society, numerous classification issues have been related to the terms used to identify racial or ethnic groups. The terms used to describe African Americans have changed over time, especially during the 20th century. Until the 1990s, the LCSH administrators had a strict policy of not changing terms for a subject category. This was enforced to tighten and eliminate the duplication or confusion that might arise if subject headings were changed. As a result, the term 'Afro-American' to describe African-American topics in LCSH was used long after it lost currency and acceptance in the population. In 1996 LCSH decided to allow some alteration of terms to better reflect the needs and access of library users. But, many common terms, or 'natural language' terms, are not used in LCSH. This may limit the ability of users to locate items. Research has increased in Library and Information Science faculties related to identifying and understanding the cultural and gender biases that affect the terms used in LCSH; these may limit or deprive library users access to information stored and disseminated in collections. In 2016 LCSH was subject to national news coverage when the Library of Congress decided to revise the heading 'Illegal aliens', an action opposed by congressional Republicans. Sanford Berman, a notable American science scholar on this subject, has noted the difficulty in finding material on certain topics, such as various denialisms, because the Library of Congress has not yet incorporated the natural language terms for them, for example, climate change denialism, into LCSH. As ideas about human sexuality have changed in the United States since the late 20th century, the LCSH has been criticized for biased organization and description of materials on sexuality. For instance, works about heterosexuality are scarcely labeled as such in LCSH; this suggests that heterosexuality is the norm and only queer sexuality needs a separate classification.

Data access

The Subject Headings were formerly published in large red volumes (currently ten), which are typically displayed in the reference sections of research libraries. They also may be accessed online in the Library of Congress Classification Web, a subscription service, or free of charge (as individual records) at Library of Congress Authorities. The Library of Congress adds new headings and revisions to LCSH each month. A web service was set up by Ed Summers, a Library of Congress employee, circa April 2008, using SKOS to allow for simple browsing of the subject headings. lcsh.info was shut down by the Library of Congress's order on December 18, 2008. The library science and semantic web communities were dismayed, as expressed by Tim Spalding of LibraryThing. After some delay, the Library set up its own web service for LCSH browsing at id.loc.gov in April 2009.

Usage Timothy Binga, director of libraries at the Center for Inquiry, notes issues that make it more difficult to use the standardized language of LCSH to find material. These include systems that allow patrons to informally tag materials in the catalog, book creators and publishers who do their own cataloging, and the incorrect application of LCSH to controversial material. Increasingly, the use of hyperlinked, web-based Online Public Access Catalogues, or OPACs, allow users to hyperlink to a list of similar items displayed by LCSH once one item of interest is located. But, because LCSH are not necessarily expressed in natural language, many users may choose to search OPACs by keywords. Moreover, users unfamiliar with OPAC searching and LCSH, may incorrectly assume their library has no items on their desired topic, if they chose to search by 'subject' field, and the terms they entered do not strictly conform to a LCSH. For example, 'body temperature regulation' is used in place of 'thermoregulation'. The easiest way to find and use LCSH is to start with a 'keyword' search and then look at the Subject Headings of a relevant item to locate other related material.

Criticism

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Library of Congress Subject Headings

Start with the simplest possible case. Write down what Library of Congress Subject Headings claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Library of Congress Subject Headings before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Library of Congress Subject Headings ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Library of Congress Subject Headings

In research: Library of Congress Subject Headings appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Library of Congress Subject Headings in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Library of Congress Subject Headings is common in secondary-school and first-year university syllabi. It links to neighbouring topics Controlled vocabularies, Library cataloging and classification, Library of Congress, so understanding it makes those chapters shorter.
In everyday life: Look for Library of Congress Subject Headings outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Library of Congress Subject Headings in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Library of Congress Subject Headings means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Library of Congress Subject Headings out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Library of Congress Subject Headings in simple terms?

Why does Library of Congress Subject Headings matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Library of Congress Subject Headings?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Library of Congress Subject Headings.