[Sigia-l] The A>B, B>A problem

[Leonard Will]

In message <418B91D4.7040103 at poorbuthappy.com> on Fri, 5 Nov 2004, Peter
Van Dijck <peter at poorbuthappy.com> wrote
>Is there a name for the problem when, if you are stuck with designing a
>simple hierarchy for the web, you have to choose between "Wine > France
>> ..." or "France > Wine > ..." and there is no best choice because
>users have differing needs? I know this problem has come back in almost
>every taxonomy (that is a simple hierarchy) that I have ever done. So I was
>wondering if there exists a name for it? Library scientists?
>
>If not, we should probably coin one...
>
>Cheers,
>Peter
>(I'll kick the first person who mentions facets. That's not the question.)

Well it is, but there are two issues which are far too often confused.

As expressed here, you are combining concepts from two different facets:
place and material. The question you are asking is normally expressed in
the information science profession as asking what the citation order of
these facets should be. There is no simple answer, but two general
guidelines are widely used.

The most famous one is that of Ranganathan :
PMEST - personality : matter : energy : space : time
where "personality" means the core concept or focus of the area covered
by the classification scheme ("taxonomy" if you must :-) )

In your example "wine" might be considered as "personality" or "matter",
depending on the scope of the scheme, and in either case it would
normally precede the concept "France" which belongs in the place facet
("space").

A more extensive list for the citation order of facets is that developed
by the Classification Research Group (of which I am a member):

thing - kind - part - property - material - process - operation - system
operated on - product - by-product - agent - space - time - form

This may be altered in some areas, but it gives a generally useful
order. The main thing is to have some such rule in mind rather than
making arbitrary decisions as each new concept is introduced, which
makes your hierarchy unpredictable.

Characteristics of division have been mentioned, and I think it is
important to distinguish arrays based on these from facets. I am a
member of a working party which has prepared a draft revision of the
British Standard for thesaurus construction (BS5723, currently identical
to ISO 2788); I'll forward a copy of the announcement of this to the
list in a separate message. The draft includes the following
definitions:

==================== beginning of quote from draft standard ======
2.1 : array
= group of sibling terms

EXAMPLE In the following, outerwear and underwear are sibling terms in
the same array.

clothing
     outerwear
          overcoats
     underwear

2.2 : characteristic of division
= attribute by which a concept can be subdivided into an array of
narrower concepts each having a distinct value of that attribute

EXAMPLE In the following, age group is the characteristic by which the
concept of people is divided.

people
     (people by age group)
     children
     youths
     adults

2.11 : facet
= high-level grouping of concepts of the same inherent category

NOTE Examples of categories that may be used for grouping concepts into
facets are: activities, disciplines, people, materials, living
organisms, objects, places and times.

EXAMPLE 1 Animals, mice, daffodils and bacteria could all be members of
a living organisms facet.

EXAMPLE 2 Digging, writing and cooking could all be members of an
activities facet.

EXAMPLE 3 Paris, the United Kingdom and the Alps could all be members of
a places facet.
==================== end of quote from draft standard =========

A concept cannot belong to more than one facet, because facets are by
definition mutually exclusive. A concept can belong to more than one
array within the same facet, because more than one characteristic of
division may apply: for example "boys" may be in a "people" facet and
can occur in the two arrays headed by the node labels "(people by age)"
and "(people by sex)".

A great deal of confusion arises because this distinction between facets
and arrays is often not observed.

There is a lot more that could be said, but this message is long enough
so I'll wait to see whether any discussion ensues.

Leonard Will

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