Innovation is a team sport, and no one describes this better than Professor Keith Sawyer in his book, Group Genius. Keith's blog, Creativity & Innovation, highlights one of the most significant aspects of successful innovation - that groups of people are likely to be more creative than individuals working on their own. His latest example of Pixar and Disney Animation Studios illustrates this well. “Creativity involves a large number of people from different disciplines working together to solve a great many problems…A movie contains literally tens of thousands of ideas.” (Ed Catmull, Pesident of Pixar and Disney Animation Studios) Why are groups so effective? What is the optimal group size? What is the best way to leverage the group dynamic? As a practitioner and teacher of innovation, I have witnessed group innovation many times in many settings, and I observe three factors that might explain why teams outperform individuals at innovating.