"adding manpower to a late software project makes it later" -http://en.wikipedia.org/wiki/Brooks%27s_law
"If anything can go wrong, it will." -
http://en.wikipedia.org/wiki/Murphy%27s_Law
Remember those: too much people = bad.
It can be even thought of as a
People vs Work done chart.
It would be a parabola, you need to find the balance