In this series of blog posts, I’ve been talking about project estimation. But I’m a tester, and if you’re reading this blog, presumably you’re a tester too, or at least you’re interested in testing. So, all this has might have been interesting for project estimation in general, but what are the implications for test project estimation? Let’s start with the tester’s approach: question the question. Is there ever such a … Read more
Last time out, we determined that mucking with the estimate to account for variance and surprises in projects is in several ways wanting. This time, we’ll make some choices about the tasks and the projects, and see where those choices might take us. Leave Problem Tasks Incomplete; Accept Missing Features There are a couple of variations on this strategy. The first is to Blow The Whistle At 100. That is, … Read more
In the last post, I talked about the asymmetry of unexpected events and the attendant problems with estimation. Today we’re going to look at some possible workarounds for the problems. Testers often start by questioning the validity of models, so let’s start there. The linear model that I’ve proposed doesn’t match reality in several ways, and so far I haven’t been very explicit about them. Here are just a few … Read more
There has been a flurry of discussion about estimation on the net in the last few months. All this reminded me to post the results of some number-crunching experiments that I started to do back in November 2009, based on a thought experiment by James Bach. That work coincided with the writing of Swan Song, a Better Software column in which I discussed The Black Swan, by Nassim Nicholas Taleb. … Read more
The Agile community (to the degree that such a thing exists at all; it’s a little like talking about “the software industry”) appears to me to be really confused about what “done” means. Whatever “done” means, it’s subject to the Relative Rule. I coined the Relative Rule, inspired by Jerry Weinberg‘s definition of quality (“quality is value to some person(s)”). The Relative Rule goes like this: For any abstract X, … Read more
Eric Jacobson has a problem, which he thoughtfully relates on his thoughtful blog in a post called “How Can I Tell Users What Testers Did?”. In this post, I’ll try to answer his question, so you might want to read his original post for context. I see something interesting here: Eric tells a clear story to relate to his readers some problem that he’s having with explaining his work to … Read more
Part of the joy of producing this blog is in seeing what happens when other people pick up the ideas and run with them. That happened when I posted a scenario on management mistakes a few weeks ago, and Markus Gärtner responded with far more energy and thought than I would have expected. Thanks, Markus. Last week I posted a transcript of a transpection session between me and James Bach. … Read more
A transpection is a dialog for learning. James Bach describes it here. Transpection is a technique we use a lot to refine ideas for presentations, for articles, for our course, or for our own understanding. Sometimes it’s all of them put together. Transpective sessions with James have led me sharpen ideas and to do work of which I’m very proud—on test coverage, for example (articles here, here, and here). Sometimes … Read more
Last night I booked a hotel room using a Web-based discount travel service. The service’s particular shtick is that, in exchange for a heavy discount, you don’t get to know the name of the airline, hotel, or car company until you pay for the reservation. (Apparently the vendors are loath to admit that they’re offering these huge discounts—until they’ve received the cash; then they’re okay with the secret getting out.) … Read more
In our Rapid Testing class, James Bach and I like to talk about an underappreciated tester resource: disposable time. Disposable time is the time that you can afford to waste without getting into trouble. Now, we want to be careful about what we mean by “waste”, here. It’s not that you want to waste the time. You probably want to spend it wisely. It’s just that you won’t suffer harm … Read more