Faceted classification and logical division in information retrieval

8.5. Alternative citation orders

The problems posed must be seen in the context of the purpose of library classification, which does not seek to educate the specialist (in the above case, art historians and art critics) in the structure of their subject but to provide an instrument that assists the ready locating and relating of records according to their content. It also emphasizes that the arrangement within a subject in a general classification may not serve the needs of a special collection, e.g., a college library may want its arrangement to reflect as far as possible the curriculum in the subject as taught in that college. The original Bliss classification was notable for its provision for alternative arrangements to meet this problem. BC2 has followed and extended this policy, and it is worth noting that a number of college librarians using it prefer to use some of its alternative arrangements for the very reasons mentioned. In this way, they enjoy the comprehensive analysis, vocabulary, and notation of the general scheme and yet manage to fit it to their special needs.

9. FILING ORDER OF CLASSES

This is the sequence in which the individual classes, simple or compound, file one after the other in a linear order. It is quite different from citation order. The latter is analogous to the order of constituents in a telephone directory entry--Surname, Forename, Designation (Dr., Sir, etc., perhaps). But whereas the second dimension in the directory (the A/Z filing order of the names) has nothing in common with the first in the manner of its construction, this is not so with the classification, in which filing order is determined to a large extent by the citation order. Filing order has two quite separate components: first, the filing order of the facets and arrays when each facet and each array is treated as a single block of classes, and second, the filing order of the individual classes within each array.

9.1. Facet filing order

This is the order in which the individual facets (each regarded as a block of classes) file, one after the other. It is usually the reverse of the citation order, i.e., the first-cited facet files last, the second-cited facet files next to last, and so on. This is entirely due to its need to observe a general before special order.

General before special (decreasing extension). This principle is quite independent of faceted classification. It is considered here because its implementation requires what is called an inverted order in the filing of the facets and of the arrays within them. It is defined thus: a class that completely contains another class should file before that class. The observance of this rule seems to be almost a universal expectation; perhaps it reflects a folk-awareness of the holistic principle of distinguishing the wood from the trees. For example, a work on marketing is expected to file before one on the specific forms of marketing (retailing, etc.) and a general work on retaining before its specific forms (self-service retailing, franchise, etc.).