SUPPORTING EVALUATION IN DESIGN

Design problem-solving requires designers to be creative and to expres s evaluative judgments. Designers propose successive partial solutions and evaluate these solutions with respect to various criteria and con straints. Evaluation plays a major role in design because each success ive evaluation step guides the course of design activity, However, eva luation of design solutions is difficult for both experienced and inex perienced designers because: (1) in complex domains, no single person can know all the relevant criteria and constraints, and (2) design sol utions must be evaluated from multiple, and sometimes conflicting, per spectives. Domain-oriented design environments have been proposed as c omputational tools supporting designers to construct and evaluate desi gn solutions. Critiquing systems embedded in these environments suppor t evaluation activities by analysing design solutions for compliance w ith criteria and constraints encoded in the systems' knowledge-base. T o investigate the impact of such systems, we have designed, built, and evaluated a domain-oriented design environment for a specific area: p hone-based interface design, Professional designers were observed usin g the design environment to solve a complex design task. Analyses of t hese design sessions enabled us to identify reactions common to all de signers, as well as reactions depending on the designers' level of dom ain experience.