An Overview of Library Classification Systems

Written by Michael Olenick, Sr. Content Business Analyst at ProQuest

With many different subject classification systems where most are referred to by their acronyms, it is sometimes hard to tell your BISAC from your BIC from your LCSH. Here is a brief overview of some classification systems that are used by our content team.

BISAC subjects have been the North American book industry standard for over 25 years. The schema is licensed and maintained by the Book Industry Study Group (BISG) and was originally designed to mirror subject areas one might find in a bookstore. Updated annually, they consist of around 5000 subjects in 54 broad sections. Nine-character codes of the form AAA###### identify subjects consisting of the section name and one or more subheadings (e.g., "HIS020000 HISTORY / Europe / Italy"). The first three characters identify the subject area. Subjects themselves are often grouped hierarchically within each section (for example, the subjects following HIS020000 are "HIS060000 HISTORY / Europe / Poland" and "HIS044000 HISTORY / Europe / Scandinavia"). Further information can be found at https://bisg.org/page/bisacedition.

BIC subjects are essentially the UK equivalent of BISAC as created by the Book Industry Communication (BIC). However, effective Feb 2017 this schema was "frozen" and has largely been replaced by Thema. Codes consist of about 2600 variable length, hierarchical, alphanumeric codes which can be modified by 950 qualifiers of five different types (geographical, language, time period, educational purpose, special interest). Because much of the information BISAC carries in the subject can be conveyed via a BIC qualifier, there are fewer subjects but more ways to describe a book. For example, there is just the one code "HBJD European history" but this can be assigned along with over 130 qualifier codes indicating a country or other region in Europe (e.g., "1DST Italy", "1DSTA Sardinia", "1DSTC Sicily"). The codes themselves are hierarchical while the text is not (for example, "HB History", "HBJ Regional & national history"; "HBJD European history"; "HBJD1 British & Irish history"). More information can be found at https://bic.org.uk/7/BIC-Standard-Subject-Categories/.

Thema subjects are the newest subject schema. Launched in 2013 as an internationalized version of BIC, these codes are maintained by EDItEUR. Essentially the idea was to both expand BIC's subject coverage and make it less UK-centric. With input from dozens of countries, Thema is the first truly international subject schema and is available in multiple languages. Thema has the same coding structure as BIC but has expanded to about 3100 codes and over 5000 qualifiers of six different types (including a new section for Style). So now, along with "NHD European history" you can assign over 2000 geographical qualifiers for Europe alone, including nearly 200 for Italy (for example, "1DST-IT-NZLC Lake Como"). Full updates are scheduled to be issued biannually, with minor updates and qualifier additions made on an ongoing basis. More information can be found at http://www.editeur.org/151/thema/.

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