Terry Ballard

Revised February 20, 2009 by Tina Gunther and Terry Ballard

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This list started as a byproduct of a keyword inspection of the online catalog of Adelphi University in 1991. That study was inspired by a cataloger at Harvard named Jeffrey Beall, who found errors in the Library of Congress catalog, and reported on a list of test words in the journal American Libraries. Early in the process I found that words appearing more than once in the Adelphi catalog were almost always found in other OPACs of similar size or larger.

Several years ago the whole subject was given a boost thanks to Phalbe Henriksen, library director of the Bradford County Public Library in Florida, who got people talking about the problem again, and who added the very high probability typo "Geneology." Phalbe's enthusiasm for this subject inspired me to create an online discussion (A link for joining is at the bottom of the page), and it is now thriving. Since the formation of the listserv, Phalbe has been matched in volume and enthusiasm by Tina Gunther of Biola University. In particular, the past few years, Tina has acted as the Keeper of the Master List, doing a superb job of being the last word on the work that the group has carried out. For further information about this, a good article about the history of this project, written by list member Wendee Eyler can be found at, and Tina Gunther wrote a followup article in Associates with her own perspective on the project. Also, Jeffrey Beall, who has become an active member of this forum is also the most prolific author in the library literature on this topic. His latest article can be found at

Typo of the day blog.

See it at

Then for a look at the words we've covered, visit our Typo of the Day archival Wiki at

The words grouped by category of probability

Section A -- Highest Probability (117 terms with 100* hits in OhioLINK)
Section B -- High Probability (1313 terms with 16-99 hits in OhioLINK)
Section C -- Moderate Probability (1143 terms with 8-15 hits in OhioLINK)
Section D -- Low Probability (3246 terms with 2-7 hits in OhioLINK)
Section E -- Lowest probability (2341 terms with only 1 hit in OhioLINK)

There are 8160 terms in all.

2009 Chronological Color Code

Original Adelphi List, Brown= (0411 entries)
Added in 2000-2007, (427+1260+678+81+264+1139+1243+914 Black= (6006 entries)
Added in 2008, Blue= (939 entries)
Added in 2009, Red= (804 entries)
8160 total

Other formats and options

The complete list in one file, grouped by probability
New entries , Which will be showing up for the first time on the 2010 update.
The list in probability order, displayed in columns for printing purposes.
The list in one alphabet, arranged in columns There is now a second PDF that has the list in one alphabet. Click HERE.

A reader asked us for a form that could be displayed in larger print by the users: It is now available HERE as a Word Document.

New! A PDF list in 4 columns that includes entries from MoreTypos

Combined List.

Recorded hit scores may be adjusted upward, but not downward, so entries may change categories from one update to another.

In addition to words that are misspelled, there is another category of problem that we are tracking - filing indicator mistakes. This will make a book title searchable by the wrong letter in the initial word. Good bellwether words for finding these in your system are searches like "rt" or "tudy" or "tudies." The solution varies from system to system, but there is a thorough discussion of this in the archives of the list below. The single most common filing indicator is a missing indicator for a word that starts with an initial article. In many OPACs, you can find these by simply typing the search "the." If you have an Innovative system, you can make a list of all titles that have suspicious filing indicators - i.e., books in the English language with a filing indicator of 4 where the first letter of the title is not t.

A discussion list for librarians interested in this problem has been formed. Watch this page for further details.

In a similar vein, the Ohio Library Councilís Technical Services Division has announced their sponsorship of the DEWEYERROR list, a new electronic distribution list that will alert members to suspected errors in Dewey numbers in LC records. Do you, or does your library, routinely accept Dewey Decimal Classification (DDC) numbers from Library of Congress (LC) catalog records without checking them first? Or, do you not only check them, but also take the trouble to advise LC when you suspect a number is in error? If you answered yes to either of these questions, the DEWEYERROR list is available for your use. To subscribe to the list, send an e-mail to with the text SUBSCRIBE DEWEYERROR plus your name.

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