Brook's law:
Adding man power to a late software project makes it later
Not always.
I am living proof that Brook's law not always prevails. No, it's not because I'm extremely good in what I do (<joke>which I am, of course, cough, cough</joke>), it's just that Brook's law doesn't account for every possible scenario.
In this case, I was called to the rescue to perform a task that the main team could do anyway, but that could also be done by an outsider (thus saving precious time to that team), because it was a self-contained task for which no deep knowledge of the project was required. I simply (yeah, simply, I'll tell you about "simply") had to migrate a database, which proved to be a real PITA, but was doable anyway.
The project was late when I got there and was still late after I left, and the day after they told me the migration would have to be done again with some different specs over the destiny database (another PITA), but my point remains: the project was late, I was there, I finished my task, and I didn't delay the project further.
Hence, Brook's law not always holds.
Well...
jplindstrom on 2005-09-22T20:00:24
Actually, Brooks said that with the same caveat that you did. From
my notes (not quotes) when I read the book:
Tasks can be implemented in parallell only if they are independent and require no communication effort on the part of the designers/programmers. If not, the communication effort adds overhead which may overcome the effect of more people.
Correct
n1vux on 2005-09-27T19:14:56
jplindstrom is correct in his reply -- Brooks Law is usually quoted out of conext.
In justifying his law, Brooks specifically cited the increasing number of interpersonal interfaces (n**2) and the ramp-up time of the new staff (and the concomittant investment required by the existing staff in the new staff's ramp-up. If Rent on a pickup is less than on a bulldozer, or if there's a premium for early completion advantage; or if Supervisors get paid double rate
...)
Splitting non-core tasks off and out-sourcing them is out of scope for Brooks law, always was. Brooks recognized that while 9 Women can not make a baby in one month, those same 9 women CAN clear as many acres in a month as one woman could in 9 months (if they *each* get a bulldozer and map, fuel,
...).
(There *are* many hidden IFs regarding logistics - one working alone must do all his/her own logistics, whereas one of the 9 will be a logistics / supervisor with a pickup , so now you have 9 workers and get 8 person-months worth of work done with 9 person-months expended in 1 month, as compared to about the same 8 months worth of work done by one person in 9 months if she does her own supplies & logistics. Economies of scale may help, if the team meetings and Reporting doesn't eat the savings. The Bonus for Early Completion _should_ overwhelm the savings or overhead. Should.)
Brooks, Mythical Man Month,
http://isbn.nu/0201835959
Re:Correct
cog on 2005-09-28T09:08:24
jplindstrom is correct
Yes, he is :-)
And I'm adding that book to my list of books to buy :-)
