Teams - the Killer App?

Jerry Weinberg, the doyen of the Quality Software movement, in his landmark four-volume set "Quality Software Management" comments on models of Software Metrics - that five factors, each of which could vary productivity two-fold, were left out because they were too hard to measure.

Team Performance is one of these five [from memory].
In "Pop Management" books, there's a lot of "soft" assertions and anecdotal evidence on the value and creation of "High Performing Teams" - but where's the solid research that shows Teams Really Do Work? And what their multiplier factor is. [Jerry is much better than that. He's been an academic and reports some very nicely constructed experiments.]

"Dynamics of Software Development" by Jim McCarthy, the real-life lessons from Microsoft's C++ team, focused on team factors. McCarthys mantra is: "The Software is the Team, the Team is the Software". If there is a problem in the team, it will show up in the software. Faults in the Software are caused by failures in the team process. Team dynamics impact performance immediately and greatly.

Bob Lewis succinctly defines the difference between 'teams' and 'groups' - a 'team' needs everyone to complete the task. There are no "Sales Teams" - individuals make sales.

What I'd like to say is: "Here's the definitive reference that shows Teams improve software & I.T. productivity by a factor of 2-5".
When I find the research, you'll be the first to know.