I would like to add a "Bugs" task with a duration calculated from 20% of total project duration. Is this possible in MS Project?

If not, what are the options of adding a task that duration depends on duration of others?

2 Answers 2


The tool is not that smart. But, that said, it violates what a baseline is supposed to be. All of your packages have some level of dependencies on other tasks as well as normal variances. But once you have examined your risk, you need to create targets and firm your durations up. So if your bug package is 20% of the cumulative result of your other packages, then firm it up.

So when your schedule begins to produce variances, so too will your bug package, and that is what you manage.

Now in Agile, this might be different. I don't have experience here.


First, let me agree with Mr. Espina that this may not be wise. I'm not arrogant enough to assume that I fully understand your underlying requirement, it sounds to me like you need to add a 20% buffer to each of the development (and integration) tasks to cover quality control. Personally, I suspect that I'd add a new work package called Quality Control dependent on the development/integration work packages, and I'd assign a deliverable to that work package that would include "Estimate Technical Debt". I'd then use that to look at long term quality control process/procedures. But I digress - you know your environment better, and that is "discussion", rather than "answer", which means I'm pushing the boundaries of Stack Exchange.

To directly answer your question, it is possible to create custom fields based on the project duration (See Project functions for custom fields, and probably ProjDurConv or DateDiff). However, I've found that the functions are ... less than reliable... (I'm in the process of documenting a test case so that I can ask a clear question on Stack Exchange). The best source for getting started is probably Add the Late Indicator tool in Microsoft Project 2007.

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