This paper investigates expertise development in design – product (industrial) design in particular. The research concentrates on the modelling of design expertise. The research stands on the premise that knowledge — domain-specific knowledge in particular — plays a significant role in distinguishing a novice from an expert. The knowledge identification is based on the analysis of designers' visuals generated during the early stage (conceptual stage) of the design process. Differences and similarities between novice and expert designers during the early (conceptual) stage of the design process and how they utilise strategic knowledge are outlined. The paper also addresses the transitional process through which a novice becomes an expert and...