Project Scheduling Exercise "Cup of Tea" Workings

In a previous post I have set a simple Project scheduling exercise around making a Cup of Tea. This post includes my workings for the answers to the questions set. If you haven't yet tried the exercise, you might want to have a go before reading this in detail. Do you agree with my results?

The Cup of Tea schedule not yet levelled

Here is the schedule before any levelling has taken place. The column marked "Crit" shows the critical tasks and the finish milestone is at 14:30

Showing the same information in a Gantt chart, the critical tasks are show in Red

Note that at 10:00 David is doing too many tasks or as Project Manager would say, he is over-allocated. The process to remove this over-allocation is to level the schedule.

Levelling the Cup of Tea Schedule

Most tools have specific views to allow you to manually level the resource over-allocations. Below is a typical view:

It shows the effort allocations for David with a Gantt view below. See the 5 mins of effort by resource David for task "Pour boiling water into Mug".

An example Levelled Cup of Tea Schedule

Below is the schedule after levelling has taken place:

Most of David's non critical tasks have been moved to be in parallel to the long task "Boil Kettle" (with little effort for David). However there was also over allocation of tasks for David near the end of the schedule and eliminating this has pushed the finish milestone out to 14:50.

Adding resources to the Cup of Tea Schedule

To get back to the original duration built from the initial schedule, I would have a team mate "Rinse spoon, dry and return to drawer". This saves 20 minutes and returns the schedule to finish at 14:30. The other levelling of tasks for David in parallel to "Boil Kettle" are retained.

Finally, any other ideas for reducing the overall Project duration?

I have seen people "pour the milk into the Mug" in parallel to "Let tea brew in Mug". This shortens the duration but unfortunately it reduces the temperature of the liquid and thus the quality of the brewing process. Which only goes to show that project short cuts may achieve a quicker delivery but will the final outcome still meet the Project Quality criteria?