I think if I saw someone falling behind I would take a similar apporach to Jackie because I know when I fall behind on a project its helpful to feel like the person you are working with isn't just assuming you've been slacking or can't finish it. Giving someone the benefit of the doubt and going to talk with them about what's going on that is holding up the process leads to productive talks about issues and can bring about good solutions the person might not otherwise have found. I also agree with Adam that if it does seem like the person is just pushing the project off and not really putting much work in or fogetting about it that a few little reminders can help the person stay more on track. Letting them know at the outset how high of a priority the project is can also determine how much they will get done and by when.