This work analyses the influence of several design methods on the degree of creativity of the design outcome. A design experiment has been carried out in which the participants were divided into four teams of three members, and each team was asked to work applying different design methods. The selected methods were Brainstorming, Functional Analysis, and SCAMPER method. The ‘degree of creativity’ of each design outcome is assessed by means of a questionnaire offered to a number of experts and by means of three different metrics: the metric of Moss, the metric of Sarkar and Chakrabarti, and the evaluation of innovative potential. The three metrics share the property of measuring the creativity as a combination of the degree of novelty and the degree of usefulness. The results show that Brainstorming provides more creative outcomes than when no method is applied, while this is not proved for SCAMPER and Functional Analysis.

Studying the effects of idea-finding design methods experimentally can provide some light into their degree of usability. An experiment was carried out to study the effects that different stimuli proposed in idea-finding methods have on the design process and outcomes of four design teams, and to compare these effects with those produced by the problem-solving characteristic of the team members. Protocol analysis and outcome-based analysis were carried out. The results of the analysis show that stimuli can have a greater effect on the design activity than the influence of the designers’ problem-solving styles in the conditions of the experiment. Stimulus with SCAMPER questions favours refinement of solutions, by using a solution as a frame and the questions as sub-frames. Stimulus with images (related in shape and function with the designed object, and displayed in intervals of time) leads teams to be in a continuous flux of generation of partial solutions.