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- Hypertext -- Shouldn't it be hierarchical?
- ==========================================
-
- Hypertext should be hierarchical for the following two reasons:
-
- ┌───────────────────────────────────────────────────────────┐
- │ Hierarchies are essential to browsing │
- │ Hierarchies are essentail in communicating knowledge │
- └───────────────────────────────────────────────────────────┘
-
- These are the primary reasons for organizing information within hypertext
- formats. The central idea of hypertext is organizing information in
- non-linear formats, which support multitudes of interconnections. Such
- formats allow users to access whatever they want from wherever they start.
-
- However, there are a number of problems with this concept, such as:
-
- TRAVERSAL LIMITS Sand on a beach in California has a physical hypertext
- ================ connection to a grain of sand on a Florida beach. But
- who would want to trace the connections, or who cares?
-
- How many nodes The problem with hypertext-sand is not the concept of
- will you look interconnections in objects, but the number of nodes
- at? traversed. The same is true with information hypertext.
- There exists an upper limit in the number of
- intermediate nodes that people will examine before
- seeking alternative ways to find what they want.
-
- What is that limit . . . three nodes, five, or maybe
- Limit of 5? seven? I think the answer is less than five.
-
- If, after five tries, the user is no closer to the
- desired information than at the beginning of the
- process, most people will give up the search. Who would
- continue using a hypertext system that just presented
- five frames of unwanted information? Outside of trivia
- experts, most people would not tolerate such behavior in
- a system.
-
- PARALLEL NODES On the other hand, if each frame presented some portion
- ============== of the desired information, a user might browse through
- 10 to 15 parallel nodes before wondering why it wasn't
- put altogether as an idea unit in the first place.
-
- Consequently, although there is no reason why a
- hypertext topic can't be split into separate nodes for
- each paragraph, line, or word; in practice, linear
- information should be left linear. Idea units seem to
- be the natural boundary for each hypertext topic.
-
- INCREMENTAL The third approach to providing increasing amounts of
- HYPERTEXT? desired information with each subsequent node seems to
- ========== be a natural reward mechanism to induce continued
- browsing by a user. That implies a hierarchical order
- within the nodes browsed.
-
- Unfortunately, the originator of each of the nodes may
- not have anticipated the specific information desired or
- the sequence of nodes browsed. Why?
-
- CIRCULAR Most creators of hypertext see nodes as idea units with
- HYPERTEXT cross-references, and not as hierarchical transmission
- ========= units. Furthermore, imbedded buttons and page-based
- hypertext systems are not suited for more than three or
- four branching points per display. This hardly makes
- for efficient hierarchical systems.
-
- Actually, that's the primary problem with most hypertext.
- Hypertext cross-references in a body of knowledge tend to
- be circular <FILE77 DEFINITION> rather than directed.
-
- HIERARCHICAL The problem with most hypertext systems is that they
- HYPERTEXT aren't hierarchical <FILE74>. Yet, hypertext needs to be
- ========= hierarchical to enable people to pick up from portions of
- the structure the overall organizing patterns of that body
- of knowledge. Hierarchies are predictable; networks
- aren't.
-
- Another way of saying this is to say that hierarchies
- are prime communicators of ideas. Whereas people can
- handle information in more complex forms than a
- hierarchy, it is difficult to communicate anything more
- complex than a hierarchy to others. <FILE75 STRUCTURE>
-
- Critical reading requires assembling ideas, integrating
- them, and figuring out the appropriate context in which
- the information should be placed. However, most people
- don't read critically -- because it is too much effort.
-
- However, with information organized in strong
- hierarchies, readers have a sense of where they are
- going, why, and how everything fits together.
-
- For these reasons, I use hierarchies to categorize information in ways such
- that readers will accept them, using the following guidelines <FILE50 RULES>:
-
- Average number Good hierarchies normally have five subtopics. The
- of subtopics reasons are -- 2 is too didactic, 3 or 4 is too
- ============ symmetrical, and 6 or more is too many (unless the
- classification methods of subtopics is obvious to the
- reader).
-
- Completeness The set of subtopics should appear to cover all choices
- ============ (i.e., appear complete) as checking for exceptions is
- usually the first test readers apply to any hierarchy.
-
- Parallelism The set of subtopics should appear to divide the subject
- =========== into roughly equal categories. That's the second
- thing readers look for in good hierarchies.
-
- Sequence Finally, the order of subtopics should be natural to the
- ======== reader.
-
- If you follow these guidelines, you'll know the secret of good hypertext
- <FILE62 ORGANIZATION>. It's simply organizing information so users can rapidly
- make choices that lead to the information they desire.
-
- Just in passing, with their experience in classification, users of MaxThink
- and Houdini <FILE26 INFORMATION> know more about the essentials of hypertext
- than any other group of thinkers. How about that?
-
- Neil Larson 1/16/88 FILE28
-
- 44 Rincon Rd., Kensington, CA 94707
- Copyright MaxThink 1988 -- Call 415-428-0104 for permission to reprint
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