The preference effect in design concept evaluation

•We conduct a small-scale conceptual design and evaluation experiment.•We examine the effects of self-generated ideas on concept evaluation and selection.•Designers prefer their own ideas in concept evaluation, but not in selection.•We discuss four guidelines to mitigate the effect.•We specify further work on biased decision making in design.

Concept selection is among the most important activities in new product development, as the consequences of a poor choice may be disastrous at worst. These decisions made in the early phases of design processes are, however, poorly understood from a psychological point of view. This study set out to extend the tradition of experimental decision-making research into the field of design. We investigated whether designers systematically prefer their own ideas in concept evaluation. An experiment with eighteen professional designers was carried out to test the hypothesis. The findings show a systematic preference of self-generated concepts in evaluation tasks. We discuss the implications of this preference effect on design practice and the need for further studies on the topic.