Checking Out Diagrams in the Practitioner Exam

If you’re just focusing on the Foundation exam at the moment, you may prefer to skip this section and move on to the practice questions. If you’re going for Practitioner, you may find this part helpful.

Some Practitioner exam questions on product planning are based on supplied diagrams of which one or more contain errors. You then have to answer questions to say whether there’s an error in a particular part of the diagram. The lists here are to help you check that you really know how the diagrams should behave and so be sure that you can spot errors quickly and reel in the marks.

The most common exam approach, to date, has been to supply a Product Breakdown Structure (PBS) and a Product Flow Diagram (PFD) and say that the PBS is correct. You’re then required to find errors in the PFD, some of which are based on inconsistencies with the correct PBS. However, be well prepared for a faulty PBS as well, so you can handle any question based on errors in either or both diagrams. To check the diagrams, make sure you understand each of the following lists.

Checking a Product Breakdown Structure

These are the key points you need to cover when you analyse a PBS to find errors:

Is the top box the whole project – the ‘project product’?

Do the products correctly and completely reflect the project scenario? Don’t forget to consult the original scenario information as well as any additional scenario information supplied for the ‘plans’ section of the exam.

Are external products correctly shown as ovals (ellipses) and team products and category boxes as rectangles?

Where the scenario clearly says that a product is coming from outside the project, is it correctly shown as external, and where it’s clear that a project team is producing a product, is it clearly modelled in a rectangle?

Are the products really products – not activities, resources, sources of supply, and so on?

Does the PBS break down cleanly, or does the diagram join back up again lower down – an illegal and illogical structure?

Are there any one-to-one connections where a group only has a single product – that is, there’s a redundant level, because you can’t have a group of one? A one-to-one structure is illogical and illegal in the technique.

Checking a Product Flow Diagram

Make sure you check these points when looking at a PFD with errors:

Is the bottom box the whole project – the ‘project product’?

Do the products correctly and completely reflect the project scenario?

Going by the information in the project scenario, are any dependency arrows incorrect?

Again based on the scenario, are any dependencies missing?

Are any elements of the sequence logical where they are not specified in the scenario? For example, you can’t have the product ‘cooked food’ followed by a product ‘raw food’, because it’s not possible to uncook food.

Are internal and team products correctly modelled? Where a product is shown as ‘external’ on the PBS, has it mysteriously changed into a team product on the PFD? Similarly, has a team product on the PBS become an external product on the PFD?

Have all of the products on the PBS been carried over to the PFD or have some been forgotten?

Are all the products on the PFD worded identically to the corresponding box for the same product on the PBS – and that includes the project product at the top of the PBS and the bottom of the PFD? ‘Identically worded’ means exactly that, to the letter. ‘Garden walls’ on one diagram but ‘Garden wall’ on the other is an error.

Have any new products mysteriously appeared on the PFD that weren’t present on the PBS?

Have any category boxes been included in the PFD by mistake (the PFD only shows products, not category boxes).

Does the PFD flow smoothly through the project, with no loops joining a lower part back up to an upper part so that the project loops around forever and never finishes?