There are three reasons that Issue Boards work well for promoting consistent corporate creative performance. It has to do with 3 things that Issue Boards do very well Alignment, Serendipity, and Diverse Stimuli.
The Issue Board is centered around a central Issue. There can be only one and that is the center of the Diagram. The ensures the interests and actions of participants are directed toward the key goal. It is the central pivot point. The focus. The center. We might be able to come up with ideas with poor alignment, but we cannot be consistently creative unless we are strongly aligned toward the Issue.
Because too much focus can limit creativity, the Issue Board deliberately incorporates serenditity with having the image forms in the same picture as the issue. In order to promote discovery, what Robinson and Stern, describe as "made by fortunate accident in the presence of sagacity (keenness of insight), the Issue Board is structured to make it easy to recombine and make connections between things that may seem unconnected. By grouping and placing the forms into "concepts" it helps people tranverse the intellectual distance between abstruse connections.
The Issue Boards deliberately involve "diverse stimuli" by making participants see and think about the variety of forms. This simuli helps to provide fresh insights. And because the Issue Board is something that a group is supposed to gather around and talk about, it gives a real opportunity for people to tell other people about the stimuli they receive from the issue board and the possibilities these stimuli suggest to them.
I came across these 3 things when I was reading Corporate Creativity: how innovation and improvement actually happen by Alan Robinson and Sam Stern.