Brooks's law: why adding people makes a late project later
Twice the people, half the time? The myth of the man-month
Double the team, halve the time: the sum every boss makes when a software project runs late. Fred Brooks, who led one of the biggest software projects of the 1960s at IBM, called the unit behind it a myth.
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1
You lead a small team that builds the app of the city marathon. Miva knows the sign-up part best, and Rono knows the results. Race day is close, and the app is late.
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2
Your boss is not worried. Counted in person-months, one person working for one month (in 1975 people said "man-months"), the work is a simple sum: twice the people, half the time.
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3
In an orchard, that sum works. Each picker has a tree of their own and talks to nobody, so twice the pickers clear the trees in half the time.
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4
Your app is no orchard, though. Sign-up gives out the bib numbers, the number each runner wears, and results show them. So when Miva changes them, Rono has to know, and the sum leaves out all that talk.
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5
Someone saw this coming long ago. In 1975, Fred Brooks, who had led one of the biggest software projects of the 1960s, wrote this warning. Your boss reads it and calls for more people anyway.
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Quick check
Twice the people, about half the time. Which job works that way: flyers in every mailbox of a town, or one speech written together?
Show the answer
The flyers. Each person takes their own streets and talks to nobody. People who write one speech together must agree on every line.
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Go further
The man who called the person-month a myth.