The reason for any tester to get sucked into test estimation is a simple one. Your manager at some point in your career, will ask you how much time it will take to test the next release, project, product. You’ll probably do what I did: check what is – planned to be – in it, compare it to the previous thing you tested and come up with a number. A bit less than before if you’re more comfortable with the way of working and the system under test. A bit more if you’re feeling unsure about the quality. As a result, your manager won’t like it and you’ll probably get less than you’re asking for. Maybe, because it is an experienced manager that tricks you into believing this release is less complex or critical. Maybe because you’re not able to substantiate your estimate. Call it character, call it ambition, when this happened to me, I was not happy so I started my “quest” for a more reliable effort estimate. This quest is still going on…
I do realize that there is a discussion “against” test effort estimation in the traditional form, maybe even in “any” form. The arguments are valid as many start with “I don’t know…” (see one of my previous posts). On the dots you can put any item: my team, the product, the development team, the business, the business case, the target, the aspects to tests, where the defects are, what the deadlines are, … This is a non-limitative list and I know you can come up with many more items.
The awful truth is that we have to come up with an estimate anyway. Either we need to tell our manager what time we need to test or we need to show him what we can do within the available time. Including a high-level description of how, when, what, …. Whether we want to or not, because if we don’t do it, he will. Since I believe that craftsman are able to better estimate their work and to discuss, argument and agree about it, I think testers should do it themselves. It’s better than being told and sigh…
Especially for a tester, an estimate is an approximation, nothing more or less. We know that all kinds of things will happen that will disrupt progress, require additional time to investigate or explore, lead to a major change in the scope of the project and/or the product. I know we don’t control most of the factors that influence the required effort. But that doesn’t mean we can’t take them into account! In my opinion, we need to “collect” these factors and show the impact on the test estimate.
And by the way, against all current discussions and opinions, I do believe there is a “best practice” in estimation: you need to discuss, monitor, update, change and adapt your effort estimate continuously.