THE GROUP BRAINSTORM Born in the madmen era with scant evidence of success, group brainstorms have been a mainstay tool of agencies and marketing departments for decades. But a meta-analysis of over 800 teams published in HBR revealed this: individuals are much better than groups at generating high numbers of original ideas. What's more, the larger the group, the worse the outcome. The number of ideas declines with each additional participant in a group brainstorm. Researcher