How to Model Testing in a Project Plan

Stephen currently works in commissioning projects in the oil and gas industry.

I was in a park in Hong Kong one lovely spring day when people were putting up a stage for a festival. The public address system came on and a man said something in Chinese. Now, I can’t understand Chinese, but he was clearly saying: “Testing, testing…one…two…three.” It’s universal.

For project managers, that message carries even more importance. We all know the last thing you do in the project is test it. The question, however, is how to plan for it. Looking at a project plan, here’s an obvious way:

The problem here is that this doesn’t allow for a situation where the test fails, which is almost inevitable. I think what we really mean to say is, “Test it—and if it fails, rework it and retest it. Then repeat until it passes.”

The problem is that this cannot be modelled using a precedence diagramming method (PDM) or Gantt chart, as those do not allow for a decision node or an iteration. A decision node gives two or more possible outcomes, so it’s not possible to give a single time and cost estimate. The same goes for an iteration, which will have an unknown number of cycles.

To model this, we can look at three alternative approaches.

1. Model with a defined number of iterations. The first model is to plan for a defined number of iterations of test and rework. Here is an example with …

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Published at Wed, 05 Jun 2019 04:00:00 +0000