Whenever faced with beating deadlines, most are wont to think that adding more people to do the remaining work will help increase the chances of actually nailing that delivery. More hands, More brains, more work, no?
Unfortunately, this is not always the case. More so with software project development. There is a very good read on how this is so written by Fred Brooks – The Mythical Man-Month: Essays on Software Engineering. Essentially, Brooks is saying that “adding manpower to a late software project makes it later”.
Some factors why this is really more difficult with software development. For one, getting the additional people up to speed with the current implementation is definitely going to be a challenge. Not all would be able to easily read code and jump right onto it and fix it without introducing regressions. Another factor is to ensure all the work is synced properly. This often requires proper updates being passed back and forth especially if shifting is put into place.
All that said, it is really possible to add more brainpower especially if they are to work on a set of work that can be compartmentalized and integrated at one point in time. Integration is going to be factor but if the interfaces are defined properly, it should be manageable at some point. The timing is also going to be a crucial factor.
When deciding on whether to add more hands to the mix, one really needs to ask the team where and which items they really need help or how then can be helped for that matter. But really, why buy more people when all one really needs is buy more time?
my take 