Toolkit: Critical path analysis
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The main purpose of critical path analysis is to find the shortest time to complete the project.
Just a reminder to keep a record of all the tools in the table below. As long as you can fill in all the cells of the table, you will be able to write a successful IA.
How to
There is a family-run pizza restaurant in Town X called Bobo Pizza that serves amazing pizza and is very successful even though none of the family members running the restaurant have a business degree. The restaurant has been serving the best pizza in town for more than 10 years and looks a little bit outdated, so Bobo Pizza management shut it down for a month for renovation. A wonderful and smart IB BM student (you) who happened to know about the Bobo Pizza renovation project decided to see if it could have been completed in less than a month. All the renovation tasks and their duration are summarised below.
As you can see from the table above, task D (installation of new kitchen equipment) can only start after task B is completed (removal of old kitchen equipment). At the same time, task E (repainting the walls in the dining area) can only begin after task C is completed (removing old furniture from the dining area). Lastly, task F (new dining area furniture assembly) can only commence after task E is completed (repainting the walls in the dining area). Tasks B, C, D, E, and F are allocated to one of the two rooms in the building (kitchen and the dining area), while tasks A and G are for the entire building.
Let’s say, the wonderful IB BM student (you) has created a diagram to illustrate the project flow.
After that, the student indicated the duration of project tasks under arrows that represent the project tasks.
Next, the student numbered the nodes (circles) that represent the start and end of activities. Just for convenience.
Then, the student decided to add the earliest start times of each activity in the top right corner of each node. For example, activity A (preparation) starts on day 0, so the earliest time activities B and C can start is day 1. It takes 1 day to complete activity B (removing old kitchen equipment), so the next activity (D — installation of new kitchen equipment) can start on day 2. But it takes 2 days to complete activity C (removing old furniture from the dining area), so the next activity (E — repainting the walls in the dining area) can only start on day 3.
It was very simple for the student to calculate the earliest start times for all activities by simply adding duration to the previous earliest start time. But then the student reached activity G and got a little bit confused. Two tasks precede activity G (final clean-up): D (installation of new kitchen equipment) and F (new dining area furniture assembly). If we only consider activity D, then the earliest start time of G should be 5. If we only consider task F, the earliest start time for activity G should be 10. So, what should the student choose: 5 or 10?
The student thought a little bit and decided...