Designers largely use freehand sketching as the one way of communicating their ideas during the design process. This research aims at investigating the sketching in the conceptual design stage and to explore what measures and procedure might be appropriate method to improve the positive influence of sketching during the design process. A quasiexperiment study has been conducted with Masters students of Industrial Design Engineering at Delft University of Technology, the Netherlands. 3 control groups and 3 experimental groups consisting of 3 students underwent a design task in a given time. Whereas the experimental groups were not allowed to talk during the design process, the control groups did not received any restrictions. The experiments were recorded, observed and analyzed. This research shall contribute to a better understanding of how sketching affects creativity and quality of the final outcome, and in how far sketching enhances the value of idea development in design for Industrial Designers.