Top down versus Bottom up Classification
Top down classification is the division of a field into subfields; Bottom-up classification is the classification of terms and concepts to larger units.
"The CRG opposed the traditional top-down approach to classification, whereby areas of knowledge are predetermined and then broken down into their constituent elements. The CRG was interested in first piecing together individual elements and then determining the areas of knowledge they form." (Spiteri, 1995).
The six fundamental steps in design of classifications are according to Mills (2004, p. 550), the first two steps are based on logical division.:
Division of the subject into broad facets (categories)
Division of each facet into specific subfacets (usually called arrays, following Ranganathan)
Deciding the citation order between facets and between arrays ["The order of importance of attributes is called citation order. Properties which are scattered by the citation order are called distributed relatives" (Broughton, 2004, p. 11)].
Deciding the filing order between facets and between arrays and the order of classes within each array.
Adding a notation
Adding an A/Z index
Are these steps contradicting Spiteri's (1995) claim about CGR and top-down analysis? Do they not seem to be a rather top down way of analyzing a domain?
Literature:
Borenstein, E.; Sharon, E. & Ullman, S. (2004). Combining Top-Down and Bottom-Up Segmentation. IN: Proceedings IEEE workshop on Perceptual Organization in Computer Vision, IEEE Conference on Computer Vision and Pattern Recognition, Washington, DC, June 2004. http://www.dam.brown.edu/people/eitans/publications/BorensteinSharonUllman-TDBUseg.pdf
Mills, J. (2004). Faceted classification and logical division in information retrieval. Library Trends, 52(3) 541-570.
Spiteri, L. F. (1995). The Classification Research Group and the Theory of Integrative Levels. Katharine Sharp Review ,#1, Summer 1995, 1-6. Available: http://alexia.lis.uiuc.edu/review/summer1995/ (Visited January 1, 2004).
http://alexia.lis.uiuc.edu/review.old/summer1995/spiteri.pdf n(Visiteded February 2006)
Wikipedia, the free encyclopedia. (2005). Top-down and bottom-up design. http://en.wikipedia.org/wiki/Top-down
Birger Hjørland
Last edited: 17-02-2006