Abstract
The development of multimodal user interfaces is a complex process that needs useful guidelines and hints. This paper summarizes the overall results from a previous experimental program and then suggests useful guidelines for creating usable and acceptable knowledge-based system (KBS) interfaces. The summary of the overall experimental results ranks three experimental conditions of multimodal interaction, according to five evaluation domains. These domains were: ability to recall, ability to use knowledge effectively, ability to use knowledge efficiently, extended usability attitudes and user acceptance. The proposed guidelines offer a set of useful hints while also describing the sources of the variance between the experimental conditions. The empirically derived and proposed guidelines were: knowledge communication from a single point of contact, audio-visual metaphors to tackle information overload, task complexity and knowledge-intensity as key factors, and socially rich presence which allowed for the first impression to last longer. These guidelines have presented a roadmap for both researchers and practitioners working within the field of knowledge-based software engineering (KBSE).