LADDERING - TECHNIQUE AND TOOL USE IN KNOWLEDGE ACQUISITION

Laddering is a structured questioning technique derived from the reper tory grid technique, enabling a hierarchy of concepts to be establishe d. Previous empirical studies have demonstrated its utility for knowle dge elicitation in two classificatory domains. In this paper, three ex perimental studies of laddering are described. In experiment 1, the te chnique was used in another classificatory domain, metallic corrosion, and the effects of repeated exposure to the technique and feedback, i n the form of Pseudo-English Production Rules, were investigated. Thes e variables had no effect on the productivity of the technique. Experi ment 2 compared the laddering technique with three other techniques in a medical diagnostic domain. As in previous studies laddering was fou nd to be the most productive technique despite the change in the type of domain about which knowledge was elicited. In experiment 3, the pre ferences of subjects interviewed using two versions of the laddering t echnique, ''textual'' and ''graphical'', were compared with those obta ined when the subjects were interviewed using a computerised laddering tool. Although the ''gain'' obtained in the three conditions varied, the group of subjects did not prefer one type of laddering to another. The laddering tool used in the experiment was designed as one tool in an integrated Knowledge Engineering Workbench (KEW). The potential fo r synergy between the laddering tool and other knowledge acquisition t echniques implemented within KEW is explored. Guidance and advice conc erning the appropriate context to employ laddering within the knowledg e acquisition process is provided.