Brooks's law: why adding people makes a late project later
Sequential tasks: why some work cannot be split, however many people you add
A baby takes nine months, however many people you put on it. Part of every software project works the same way, and no new hire can speed it up. How do you spot that part?
-
1
First, how late is the app? Two of the four months are gone, and only a quarter of the app is done.
-
2
More people sound like the answer. Fred Brooks, the man of the 1975 warning, had a famous reply: a baby takes nine months, however many people you put on it.
-
3
Your app has work like that too. When results show a wrong time, someone finds the bug, fixes it, then tests again, and each step must wait for the one before. A step like that is called a sequential task.
-
4
So while Rono fixes, you can only wait for your turn. However many people join, sequential tasks set the shortest time the app can take.
-
5
Luckily, most of the app is not one long chain: sign-up and results hold plenty of work that people can share. That is all your boss needs to hear. On Monday, your team of three becomes a team of seven.
-
Quick check
A long fence needs two coats of paint, and each coat must dry for a day.
Show the answer
No. Twenty painters put each coat on fast, but the first coat still dries for a day before the second can go on. The drying is a sequential task.
-
Go further
Two more words for work that waits its turn.