A tool for the analysis and interpretation of usability data

This paper describes the main characteristics of the VISNU (Validation of Intelligent Systems aNd Usability) tool. This tool has been designed to assist developers in validation and usability analysis processes of computerised systems. The usability branch of the system includes several modules that permit to apply three types of usability analysis: heuristic, based on the collaboration of experts; subjective, based on the opinion of users; and empirical, based on the actions of users. One of the primordial goals of the system developers has been to integrate different evaluation methods to obtain information which could not otherwise be obtained. For example, the integration of heuristic results (such as GOMS analysis) with empirical results (such as execution logs). Another important goal pursued by the authors is that the usability data obtained with the tool should be accompanied with an interpretation or, at last, with facilities to perform this interpretation.