The bibliographic advantages of a centralised union catalogue for ILL and resource sharing.

This paper examines some of the bibliographic advantages of a union catalogue with a central database over a distributed, or "virtual," union catalogue. Such advantages may be worth considering when a library network makes a decision about which system model to adopt as the basis of a document delivery service. The nature of these bibliographic advantages is discussed in the context of interlibrary document delivery, as are the circumstances which produce them, and make them more significant. A brief study of the extent to which two major library catalogues in Singapore have diverged following the adoption of a distributed model, is reported. This indicated that the bibliographic content of a distributed union catalogue may be significantly poorer than that of a central database, and in particular in terms of more: (1) duplication; (2) inconsistency; (3) errors; (4) omissions. There are at least four important reasons why this may be so, since in a centralised system: (a) record duplication is caused only by cataloguer error; (b) it is easier to implement quality control mechanisms; (c) cataloguers are likely to make greater efforts to adhere to agreed standards and policies; (d) records are more likely to get amended and enhanced through the work of other libraries. [ABSTRACT FROM AUTHOR]