Numerous concept generation methods have been developed that can assist an engineer in the initial phases of design. Unfortunately, limited empirical data is available to guide users in selecting preferred techniques. This study systematically investigates underlying factors of four well-used and documented techniques: Brainsketching, Gallery, 6-3-5, and CSketch. These techniques are resolved into their key parameters and a factorial experiment is performed to understand how the key parameters affect the outcomes of the techniques. The factors chosen for this study include: how ideas are displayed to participants (all are viewed at once or exchanged between participants, "rotational viewing") and the mode used to communicate ideas (written words only, sketches only, or a combination of written words and sketches). This study also provides a method for measuring the quantity of ideas generated when the ideas are represented in the form of both sketches and words.A number of interesting findings are produced from the study. First, the study shows that individuals gain a significant number of ideas from their teammates. Ideas when shared, can foster new idea tracks, more complete layouts, and diverse synthesis. Second, the systematic exchange of a set of ideas between participants produces a greater quantity of ideas than having all ideas displayed in a gallery form. This result shows that techniques like 6-3-5 or C-Sketch, where each person views only a subset of all the team's ideas at any given time, are more likely to produce a larger quantity of ideas than techniques where individuals can continuously view all the ideas the team has generated. Finally, as teams developed ideas, the quality improved. This result is a consequence of the teamsharing environment and, in conjunction with quantity of concepts, validates the effectiveness of group idea generation.