Sunday, April 23, 2006

A Sample of Practices Interdependencies

More than once, I have got the kind of inquiry as "I'd like to adopt agile(XP) practices, which ones do you think that I should try first. It is always a hard question.

One main reason is that I very much intend to say "every team member should have the XP book by hand, the principle up on the wall, be open-minded and try to adopt the whole practices as a whole". It might sound intimidating but here is the reason:

All These Practices are Related
All these practices are supporting each other. I know it has been spelled out since day one that XP came out, but I still think it is a point that gets forgotten sometimes, especially when the team is under pressure.

In one of the training engagement that I was involved in, after some training sessions of several practices that we think the client needed, in an effort of making sure that the student understand that these practices are much better working together, we created a little dependency diagram using Graphviz.

We did it by creating the graphics file as following (detail omitted):

digraph g {
"Collaboration" [label="Collaboration"];
"Collocation" -> "Time-Boxed Iterations and Releases";
"Collocation" -> "Continuous Improvement";
"Test First" -> "Collocation";
"Test First" -> "Collaboration";
"Test First" -> "Automated Testing";
"Time-Boxed Iterations and Releases" ->"Collocation";
"Time-Boxed Iterations and Releases" ->"Collaboration";

The result was pretty staightforward:

Of course, in the presentation that we gave it looks a lot nicer with bi-directional arrows and stuff. But the idea is the same, you cannot pull one out without affecting the whole picture.

On the other hand, if you want to adopt the practices, trying them one by one will probably only make things slower and harder.

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