Y'all know the famous maxim from Fred Brookes: "Adding manpower to a late software project makes it later." (see addages named after people at wikipedia)

Yet big, late projects constantly get more people added to them.

Just today we heard about a large local project, to which far too many more resources have just been added. Why? we asked, why?

There's a rarely mentioned side effect of adding more people to a project: momentum.

Yes: Adding more people will make a project cost more per day.

Yes: It will slow down the daily progress, making it take longer.

And Yes it will lower the quality of the output, as personal responsibility becomes diluted.

But:

Adding more people may decrease the velocity, but it increases the mass enough to give a larger overall momentum.

And a larger overall momentum makes it harder to stop.

The people who make the decision to add more people are desperate to keep the project moving. In their mind, the only way to fail is to have the project canned by higher powers.

Budget overruns are not failure. Time overruns are not failure. The only true failure is if the entire project is stopped.

An object with huge momentum is harder to stop. Throw in consultants. Throw in hardware. Throw the bike on! We're gonna ram our way through! Unstoppable!

The problem with huge momentum is that when it does stop it makes a hell of a mess.

To stretch the metaphor: A fast moving train can still be derailed.

To mix a metaphor: assigning blame becomes a fruitless task. Blame is spread over a larger area.

Once failure is big enough, it becomes a success on other levels. Think titanic. Think war. Think 'time to polish your resume'