Test estimation

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In my opinion, one of the most difficult and critical activities in IT is the estimation process. I believe that it occurs because when we say that one project will be accomplished in such time by at such cost, it must happen.

If it does not happen, several things may follow: from peers' comments and senior management's warnings to being fired depending on the reasons and seriousness of the failure.

Before even thinking of moving to Systems test at my organization, I always heard from the development group members that the estimations made by the Systems test group were too long and expensive. Then, when I arrived at my new seat, I tried to understand the testing estimation process.

The testing estimation process in place was quite simple. The inputs for the process, provided by the development team, were: the size of the development team and the number of working days needed for building a solution before starting systems tests.

The testing estimation process said that the number of testing engineers would be half of the number of development engineers and one third of the number of development working days.

A spreadsheet was created in order to find out the estimation and calculate the duration of tests and testing costs. They are based on the following formulas:

Testing working days = (Development working days) / 3.

Testing engineers = (Development engineers) / 2.

Testing costs = Testing working days * Testing engineers * person daily costs.

As the process was only playing with numbers, it was not necessary to register anywhere how the estimation was obtained.

To exemplify how the process worked, if one development team said that to deliver a solution for systems testing it would need 4 engineers and 66 working days then, the systems test would need 2 engineers (half) and 21 working days (one third). So, the solution would be ready for delivery to the customer after 87 (66+21) working days.

Just to be clear, in testing time, it was not included the time for developing the testcases and preparing the testing environment. Normally, it would need an extra 10 days for the testing team.