Id Software’s John Carmack has had a few things to say about the progress of Doom 4, saying that they are aiming to deliver a high quality multiplayer experience.

Once Rage is shipped the studio will turn all of their attention to Doom 4 and really start work on development.

Speaking to Gamespot he had the following to say;

“I know we’re not supposed to talk about it, but I’ll tell you a couple
of things. (Looks at media minder across the table.) So, as soon as Rage
ships, the core tech team moves over to start making things happen on
the Doom 4 project,”

“There’s me and the systems programmer types that have been on Rage for
so long. We’re going to move over to the Doom team and a lot of
resources are going to migrate over there. And that’s a necessary and
key aspect of being a larger company; it gives us this ability to
migrate people between the projects because it was something that we
were really feeling the pinch before this.”

“If you’ve got 50 people working on a project, it’s not useful to have
all of them on day one on there; you really want to have a smaller team
building things. Then at the end now, we would have a hundred people on
the team.”

Source: Gamespot