There's a discussion on a mailing list about a partially committed-to project: there aren't enough people on the project, the people don't have the time to do the work because they are interrupted all the time by support of previously released applications. The only people available are part-time people who are not available when the rest of the team is available.
Management has not committed to the project, nor to the team. In a spirit of generosity, let's assume management is running too fast to think. If you have management like this, see if you can get them to sit still to remember their math. When a project is fully committed-to, each person on the project can supply an entire person's worth of effort to the project. If you have 8 people, that's 8 people's worth of effort. But if you have 8 people, and each can supply only a half a person, you can get a maximum of 4 people's effort minus the context switching cost. Adding more people who are only part time increases the number of communication paths (which decreases what any given person can do because of the time needed for communication) and decreases the total number of people available, because each person does more context switching.
Partially-committed projects are not projects you can predict anything about. Yes, they have people assigned to them. Yes, they even make some progress. But how can you predict anything about the project? You can't use velocity, you can't use the rate at which anything has been done, because you can't tell if that rate can be repeated in the future. You can't use an informal way to count features or phases, because your past project behavior is not predictive of future behavior.
If you want more predictable projects, the management team or some other leadership body must make decisions about whether to commit to a project or not. That's what the project portfolio is all about. Without a portfolio, you have unpredictable projects. With a portfolio, you have a chance of predictability.
But what's worse is the implicit message management says to the team. “This project is not important enough for us to commit to. But we want you to.” Not a good message.