Idea visualization is a critical tool in a product development process. From early idea sketches to 3D prototyping, designers often visualize ideas for themselves and others in the process of feedback and refinement. The viewers of these ideas (clients, investors, collaborators, and consumers) rely on these visual presentations to evaluate the potential of a designer’s idea. Although sketching ideas is common practice in the product design industry, little is known about the extent to which presentation quality influences viewers’ evaluations of ideas. This paper examines the power of product sketch quality on perceived idea evaluation. In the present study, a total of 400 participants were asked to evaluate a set of product ideas presented with and without a sketch. The results show that when product sketches were presented, the participants were heavily influenced by the sketch quality when evaluating the value of the idea, and the concept ratings were somewhat different when sketches were not present. The results imply that viewers’ perceptions of idea worthiness are possibly dependent on how an idea is visually presented.