Brooks' Law states that adding more people to a late project only makes it later.
It can be simplified like this: "Nine women can't make a baby in one month."
This is for software projects, and I read about it in college, but I believe it can be applied to anything that needs a rapid turnover within short deadlines.
The concept is simple. I took some of this from Wikipedia.
1. It takes some time for the people added to a project to become productive. Brooks calls this the "ramp up" time. When you add people to a project, they need to be brought up to speed by existing project members. This will cost time for the new additions, as well as the originals. Mistakes will be made. Clarification, repeat clarification, as the new ones and the originals adapt to each other. Social dynamics will change. This will all take time.
2. Communication overheads increase as the number of people increases. The number of different communication channels increases along with the square of the number of people; doubling the number of people results in four times as many different conversations. Everyone working on the same task needs to keep in sync, so as more people are added they spend more time trying to find out what everyone else is doing.
Managers of people need to be aware of Brooks' Law. If they want to add anyone anywhere in their organisation, or move them around, they need to be able to foresee how timing will be affected.
People talk about optimising all the time. Like say, a plant has four machines producing 200 cans of bullshit an hour. Purchasing a new machine will get you 50 more cans in an hour. People are not machines, and even with machines, there is downtime with maintenance and other complications. Can the supply queue get stuff to the fifth machine in time? When the machine is down, what do you do with a queue that is optimised for five machines? Can the other four handle the extra load?
My motherboard busted one capacitor, which in time became four capacitors, incapacitating the whole motherboard. This is because the loss of one capacitor burned out the other three that had to take its load.
Brooks' Law said that adding people to the beginning of the process, not in the later stages, have come up with better results. I am inclined to agree with him. All the ramp up time associated with added personnel can be offset with the performance we get from experienced and knowledgable workers at the end.
Oh well. Just thinking.