I agree with Pawel,
I'd say that no matter the level of expertise, when a new member is added in a team
especially in a project that is overdue and deals with pending issues, it will undoubtly cause a slow down.
There are indeed factors to take into deep consideration on both sides.
Let's face it, I don't know about you, but I've worked on
a fair amount of projects and even if some firms claim to use the same MS technology
[even to be the best in the field and give formal training formation to newcomers when it's not always the case...],
no one uses the same code logic and architecture in every context.
If things were that easy, we could all sit back and take a big break...
Reality shows that it's not the case, each new project brings a new challenge.
A lot of factors [both technical and human] can vary and interfer from project to project.
I'd say the analogy of nine women who cannot give birth to a baby in one month is perfectly
true, still a lot of team or project managers can yet picture the basic concept.
Too often their own reputation comes first, they have to deliver a product right on time no matter what
upon a client's requests, otherwise their own job might be in jeopardy... right?
I've ended a big project recently. We were a small team of 4 senior developers with few young developers to help us with unit testings tasks.
We started the project nearly all from scratch and we managed to deliver the product on time exactly as the client requested. We even brought more extras in bonus.
We occasionally had to work overtime on weekend [for free..] but just like with the Olympic, the project just couldn't be postponed and
we all knew it was a one big shot deal we couldn't miss, so we didn't want to skip it.
Throughout the project, we not only learned to work and communicate together as a team, we sort of all created the architecture and
business logic of the project right form the start and I can humbly confirm that if I would have been asked to join
the same team at a much later stage in the production, let's say like a year after and in an overdue scenario...,
no matter the level of expertise, without any proper training from my fellow team members, I might have been lost in the jungle.
The bottom line... Adding new team members to a late project can often end up in a Catch 22 situation for both parties like I often seen
if not handled and managed properly.