Here are 2 recent articles that discuss why small teams are more effective than larger ones.

  1. Great Numbers, Not So Great Design, by Khoi Vinh in Subtraction
    This craft, and whatever pretensions to art it can pull off, rests so much on the efficiency of transferring ideas from the brain to the hand. This means that in its ideal form, it works best when practiced by a single person. The perfect design staff is a single designer who can conceive of and execute an idea from start to finish — a straight shot from the right brain to the wrist — maintaining the same coherent creative vision throughout. … The problem is that the structures of most larger design businesses cannot effectively facilitate the the transmittal of ideas. They don’t allow good design to happen, because they are overburdened with the organizational overhead of running a business.
  2. If you’re working in a big group, you’re fighting human nature, by Matt Linderman in 37 Signals
    When you’ve got a small group, you don’t need to constantly formalize things. You communicate and you know what’s going on. If you have a question about something, you ask someone. Formalized rules, deadlines, and documents start to seem silly. … If you’re working in a group bigger than 15 people, you’re fighting human nature.