A lifespan of a project can vary from short a week, a few months and even a year. For general 3 to 6 months project, it may involve tens of tasks and hundreds of sub-tasks, which is not easy to plan and manage if treat each of them as equal in term of importance.Therefore, we would group some project tasks into groups and reduce the number of items we have to look at at the same time. If we need to know the details, we can drill down to the task into sub-tasks within that group.
Work Group > Tasks > Sub-tasks
Now, we should have a clear picture about the hierarchy of the project task. This is what we call the ‘work breakdown structure. You might have a question if there is any optimal number of task under a work group.I would say ‘no’, the magic number I would use as a guidance is ’6′ and ’7′. It is similar to answer of optimal number of direct report for a manager. There is no definite answer, but it should be around ’6′ and ’7′.
Another note I would make here is how to group those tasks into a work group. We should always group tasks with some attributes in common. It can be ‘place’ where those activities will happen; or ‘team of people’ who will carry out all the activities, or ‘period of time’ that all those tasks need to be completed.
With this building blocks setup, we can start the time estimate for individual work group.