The good old Mythical Man Hour.
(In simple terms, as the number of people increases, the communications overheads also increase, generally faster, so if you have more people a greater proportion of time is wasted, hence work done doesn’t increase proportionally to the number of people. Or if you just want to inform management that more people won’t simply mean the work gets done much faster just give the example of “If takes 9 months for a woman to make a child, it doesn’t mean you can get 9 women and make a child in one month”)
Diminishing Returns is the concept on a broader scale here
Ie: the more you add the less you get from adding, to the point of it becoming a complete negative
Or if you just want to inform management that more people won’t simply mean the work gets done much faster just give the example of “If takes 9 months for a woman to make a child, it doesn’t mean you can get 9 women and make a child in one month”
Management: “I don’t have time for theoretical discussions. Marketing says this releases in two weeks and you better get it done. Do you need more resources?”
“It can’t be done in this time frame.”
“Should’ve come and asked the experts how long would it take before accepting marketing’s estimates”
“So either find us more time or chose what we’re going to drop for the release”
And yeah, I’ve used this. (Then again, I’m pretty senior and seen and done a lot)
