A study, reported on Columbia ideas@work, distinguishes between two kinds of diversity. Diversity of social networks varies according to how commonly and well team members knew each other before joining the team; diversity of demographics varies according to race, age, gender, national origin, religion and other mostly-innate characteristics.
The research, which looked at 1,518 project teams at a contract R&D firm and measured team effectiveness by timely completion of its project, showed that demographic diversity had a negative effect on “internal density,” whereby team members already part of other team members’ networks “get a running start in working together.” Social network diversity had no effect on internal density.
This research suggests that a law department manager staffing a team for demographic mix will create a less effective team than if the manager staffs it with members who previously knew and worked with each other. (See my post of Jan. 4, 2005 on virtual teams.)