Psychological approach to indexing: effects of the operator's expertise upon indexing behaviour

Studies of indexing have shown significant variation in the indexing terms chosen by several indexers to represent the same document. In our opinion, this variability depends on various indexing strategies used by the indexers with different expertise. Professional and novice indexers were asked to index eight books; they had to express the topics and to choose the indexing terms from an indexing language. The factors which influenced the indexing were: expertise in the indexing task, expertise in the use of an indexing language and familiarity with the subject domain. The criteria were: the number of indexing terms chosen, the rate of the intra-indexer consistency, the types of transformation made on the concepts, the indexing procedures and the objectives pursued during the task. The findings identified three indexing strategies which depend on indexers' exper tise. The first is characterised by a search for indexing terms from the document analysis stage. The second consists of identifying the generic terms in the document that allow them to quickly access the indexing language. The third strategy is characterised by a precise analysis. These results raise questions about the compatibility between knowledge representation produced by the indexing languages and the operators' representation produced by the text in order to specify assistance to indexing work.