Prediction of OPAC spelling errors through a keyword inventory

In order to find and correct spelling errors in the online public access catalog at Adelphi University, a visual inspection was performed of the 117,000 keywords indexed in the system. More than 1,000 errors were found. Certain long but common words such as administration, education, and commercial were found to generate many different misspellings. Most of the records were derived from bibliographic utilities, so the findings can be generalized to other OPACs. The same misspellings were also found in substantial numbers in CD-ROM databases. Misspellings were analyzed by the machine-readable catalog (MARC) field in which they were found, part of speech, and type of mistake. Lists of commonly misspelled root words and specific mistakes are included. In the years since the online public access catalog (OPAC) has replaced the card catalog as the primary source of bibliographic information in research libraries, much has been written about miskeyings of library users by Peters and Blazek, among others. (1,2) However, little attention has been paid to spelling errors that become a part of the database. Perhaps this is because researchers can work with logs of OPAC transactions to find the searching errors of OPAC users, but there is no easy way to get at misspellings that are in a database containing millions of words. It may be widely perceived that spelling errors in OPACs and other large databases are few in number, randomly distributed, and impossible to locate in any systematic fashion. The results of this study demonstrate that these perceptions are incorrect. HISTORY OF THE STUDY In a recent issue of American Libraries, (3) there appeared a short article describing how Jeffrey Beall at Harvard had found words that are prone to misspelling, such as Febuary or government. Librarians at Adelphi University Library in Garden City, New York, checked the keyword index in the library's Innovative Interfaces OPAC (Innopac) and found single examples of two of the ten words that were featured. According to a formula provided in the article, Adelphi had a very clean database. This was not surprising because the cataloging supervisor has described the operation as one with a history of perfectionism. However, misspelled words did show up occasionally, and the author found a way to make a thorough search of the database for such problems. In the Inoopac system, a successful keyword search will display a record that contains the word that was queried or a menu if there is more than one hit. However, if there is no matching word, it will produce a screen of choices that are nearby in the alphabet. One may then browse forward or backward looking at eight rifles per semen A trial search of the A's was performed by typing in aaaaa and browsing forward through hundreds of screens. The result was the identification of forty-two spelling errors. This justified a search of the 117,000 words that are contained in Adelphi's 310,000 bibliographic records. A complete visual check of the keyword index represented a large volume of work, but it seemed like the only reasonable way to get the problem solved. Normally, two letters were searched in a single workday. Once a potential spelling mistake was identified, the full record was called up and checked for context, e.g., langage is correct in French, but it is a misspelling in English. If it did turn out to be a mistake, the screen containing the incorrect word was printed along with the menu screen of eight words that contained the error. At the end of reviewing a letter, the printout was marked for immediate correction by a student assistant. The system allows the staff member to call up a record, identify the field with the misspelling, and substitute the correct word for the misspelled one. In going through the screens, one major problem was non-English words that contained only a single letter's difference from the English equivalent. …