Classification Scheme:

A scheme of classification is but a tool in the hands of the library to organise subjects and to serve them out in an efficient way. Therefore, it is necessary that a lot (sire and thinking should go while choosing a classification scheme for a library. Classifications schemes are of different types. Broadly speaking, there are two types, namely, Enumerative and Faceted schemes. While Dewey Decimal Classification and Rider's International Classification be-long  to the former type, Universal  Decimal Classification and Colon Classification may be considered as Faceted schemes. For details regarding these schemes, you may consult Block 4, Units 10-12 of Course III. Each classification scheme has its own merits and demerits. This makes the choice a little bit difficult. It is  easily said that  the scheme which satisfies the needs  of the library and its clientele should be chosen. Ranganathan has suggested the following points for consideration: 

• Scope of classification 
• Sequence of Basic/Main Subjects 
• Provision for New Basic/Main Subjects 
• Provision for "Systems" of exposition of a Basic Subject 
• Provision for "Specials" of a Basic Subject 
• Crisp words to denote ideas 
• Sameness of patterns in  the sequence of subjects going with different Basic Subjects 
• Objectively used postulate and principles 
• Systematic procedure for practical classification 
• Avoidance of the fault of alternative places for one and the same subject 
• Inner mechanism to find a helpful place to a new compound subject 
• Length of base of notational system 
• Provision of connecting digits 
• Hospitality in chain 
• Hospitality in array including extrapolation and interpolation 
• Agency for promoting use 
• Permanent organisation for development 

He suggests the use of four scores: 0 Poor;  1 Passable; 2 Fair;  and 3 Good  in the scheme. Perhaps, this method would  be very  good  for the choice of a scheme of classification, especially in special libraries.