Relational Indexing Applied to the Selective Dissemination of Information

Farradane's system of relational indexing, which had been previously used in a retrospective search system with good results, was further tested as the indexing language for an experimental S.D.I. system. Sections of Metals Abstracts were used for the data base of 2,820 abstracts, and forty‐three volunteer users participated in the experiment which lasted for six months. Performance was assessed by recall, precision and fallout ratios, and the ‘coefficient of association’ (Q value) and the product (recall X precision) were used as overall measures. The overall average performance was about 75% recall and 75% precision. A failure analysis was also carried out. The browsing strategies incorporated into the system were analysed, as were the profile structure, the distribution of performance measures and possible relationships between recall, precision and generality. Farradane's relational indexing appeared applicable to the different scientific area of the properties of metals and again gave good results with a greater depth of indexing. Some new features of the system were observed.