Page 231 - DLIS402_INFORMATION_ANALYSIS_AND_REPACKAGING

Information Analysis and Repackaging

Notes Hierarchies of Terms

Two-level book indexes are typically easier and faster for most users than indexes with a single
level or more than two levels. But no matter how many levels an index has, it is likely have to deal
with hierarchies of concepts that have more levels. Which is one reason two-level indexes have
become the standard in computer software texts.
How should a professional indexer (or MI) deal with a greater than N + 1 level hierarchy of terms in
an N level index? This happens all the time in computer software books now that hierarchical objects
are the basis of most programming.
Suppose one has a set of terms requiring indexing related hierarchically as TopObject, Mid1Object,
Mid2Object, LowObject. This happens frequently in computer texts about object libraries.
In order to make sure the reader can always find any of these terms on the first try you need
permutations of all terms as first-level entries, and within each first level entry permutation of all
lower level entries. In some cases it might even make sense to have a higher-order object as a subentry
to a lower-order object, but ignore such cases. So the index of the hierarchy would appear as:
TopObject
......Mid1Object
......Mid2Object
......LowObject
Mid1Object
......Mid2Object
......LowObject
Mid2Object
......LowObject
LowObject
That arrangement can certainly be created with a computer algorithm. Consider that in most real
cases there are multiple terms at each level. Suppose there are just 2 second-level terms, Mid1Object1
and Mid1Object2, and each of them has 2 third level terms, and all third level terms group 10 fourth
level terms. To completely cover them in the manner shown above would require 170 entries. Book
publishers generally will not allow a long enough space for the index to offer such complete coverage.
Indexers must make choices. This is especially true because TopObject, in fact all objects, probably
have substantive subtopics in addition to their contained objects (in computer programming texts,
for instance TopObject might have topics such as initialization, parameters, properties, or its purpose
or definition).
A method often used to offer the appearance of complete coverage is to use.
TopObject
......Mid1Object. See Mid1Object
Mid1Object
......Mid2Object. See Mid2Object
Mid2Object
......LowObject. See LowObject
LowObject

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