Double-posting is a technique used to provide multiple access points to the same information. Different readers might search for the same information using different terminology, so it is important to consider all possible variations of the main heading and provide an access point for each.
Some common uses for double-posting are the treatment of acronyms, initialisms, and abbreviations, creating entries for synonymous terms and main headings that begin with numerals.
Acronyms, initialisms, and abbreviations should be double-posted when both main headings would not appear adjacent to each other in the index.
Depending on the size of the index, these main headings may appear several lines apart:
CAD (Computer-Aided Design)
Computer-Aided Design (CAD)
Whereas, the following main headings may appear closer together:
UNESCO (United Nations Educational, Scientific and Cultural Organization)
United Nations Educational, Scientific and Cultural Organization (UNESCO)
Cross-references, if not used carefully, can clutter up an index and create extra work for the reader.
Double-posting is also used to eliminate cross-references by creating main headings for synonymous terms.
Without double-posting, a reader must flip to the preferred term ‘vehicles.’
automobiles see vehicles
cars see vehicles
trucks see vehicles
By double-posting this locator, a reader can go directly to the information they are seeking.
Numerals that appear at the beginning of the main heading require a more subtle use of double-posting. Recently a new client asked the following question,
“You list “1% for the Planet” both as its own section (I’d assume because it starts with a number) and at the bottom of the “O” section. What is the reason for it being in the O list?”
The answer is that the main heading was double-posted under “O” for readers who might be searing for “One Percent.”
The [hide text] feature of the indexing software is used to correctly sort the entry as if it had been spelled out.
1% for the Planet
[one]1% for the Planet
One of the Five Laws of Library Science is “Save the time of the reader.” By using indexing best practices such as double-posting, an indexer provides quick and easy access to information.