advantages of the Dewey Decimal Classification system
The Dewey Decimal Classification system is universal because of its
numerical notation. Since there are different alphabets, a system
based on Arabic numerals is used throughout the world.
Documents are classified by subject. Those interested or
specialized in a particular topic can find all the documents they
need under the same classification.
Three easily overcome disadvantages of the Dewey Decimal
Classification by subject and not by topic
For example, the topic of drug use is discussed in psychology
(157), sociology (363.45) and medical (616.863) books. Three
disciplines deal with the this topic in their own way. Books on
drug use can therefore have different call numbers under the Dewey
Nonetheless, an alphabetic catalogue of topics (used in both
computerized and non-computerized libraries) makes it possible to
locate these books.
A reader who needs information on drug use (or any other topic)
will consult the subject catalogue or the subject heading in a
library and documentation centre management software program. He or
she will obtain a list of all the books that deal with drug use,
regardless of the disciplinary angle from which it is studied.
The same topic can be studied within two different
Let's go back to the example of books on drug use. If a group of
authors publishes a book on all the aspects of drug use, this book
cannot be stored in three different places. In this case, the
librarian assigning the call number will determine under which
subject the book will be classified.
Again, if the reader consults the subject catalogue or the
subject heading in a library management program, he or she will
obtain a list of all the books that deal with drug use, regardless
of the disciplinary angle from which it is studied.
The length and complexity of call numbers discourages some
The Dewey call number can be regarded as an address. If I have
to meet Mr. X and I know that he lives at 641 Elm Street, the
address tells me where to go. The same is true of the Dewey call
number; I don't need to know whether Mr. X lives alone, or if he
has children, a cat or a dog-nor do I need to understand all the
intellectual criteria librarians use to determine if a book is to
be classified under such and such a call number.
With regard to the length of the call numbers, remember that
elementary and even secondary school libraries use the abridged
Dewey Decimal Classification system (no more than 3 digits after
the decimal point) to simplify the classification.
Difficulties often arise when books are arranged by people who
do not understand the decimal system. This is now less of a problem
for students since decimal notation is a compulsory topic in
elementary Cycle Two mathematics under the Québec Education
Lastly, to facilitate access to books even more, most school
libraries have decided not to use the 800 class (literature), which
categorizes works by genre, era and country. Literary works (e.g.
novels, albums) are therefore simply stored under the letter
F (for fiction) and then subdivided by the names of authors
listed in alphabetical order.