Let's start with a fairly common question:
"Ouch, we're so behind with the project, what on earth shall we do?"
A response that is just as common is:
"Add more resources! Increase head count as much, and as fast, as possible!"
Honestly, how many people have responded so spontaneously?
Over 35 years ago Frederick Brooks wrote the book "The Mythical Man-Month", where he shows a formula for how to calculate how much the delay increases in a delayed project if you add one more person. How is it, then, that so many think it'll help?
What is even worse, apart from the delay being likely to increase, is that projects with too many people involved have a tendency to lead to a large code base. It is to be expected as a law of nature. It can of course be too large a code base for many other reasons too, but this is one important factor.
Each developer would naturally like to be productive and, just like the others, add X number of lines a day. So the growth of the code base size is directly related to the number of developers.
Even if I am allergic to projects that become overcrowded over time, there's something I dislike even more. That is projects that start to be overpopulated on day one. On top of the problem with too large code base there is an additional problem with X amount of people that are waiting for something to do, which costs a lot to no avail. Pretty soon everyone starts to create their own architecture. Similarly, requirements are created wildly on speculation. The project is simply in a very bad position from the outset.
Why does this happen? I think one reason could be that many people see software development as a keyboard intensive task. Sure, it never hurts to be fast on the keyboard, but it is mostly because the keying should not distract the thinking and the mental models.
If you are twice as fast at the keyboard as your colleague is, are you twice as good as your colleague?
Perhaps, but if you believe a quote from Bill Gates where he should have said that a super programmer is worth 10 000 times higher salary than a mediocre one, your double speed keyboard skills should be a very small advantage. Probably other stuff is way more important.
When I think about it, we have a saying for this phenomenon; the adage is probably much older than Brooks's book and it goes: "too many chefs spoil the broth." So, avoid adding loads more head count on the problem at all costs.
(First published in Swedish here.)