Thursday, December 13, 2007

The Nokia Test (1): Iterations must be timeboxed

I will be doing a series of posts that discuss each element in the Nokia Test (see earlier post). In this first post, we will focus on the first element in the Nokia Test: "Iterations must be timeboxed to less than six weeks."

First, remember that the first section of the test is to determine whether a team is iterative. (The second section determines whether they are doing Scrum.)

This first element, the length of the iteration or sprint, in standard Scrum according to Ken Schwaber is one month. There are many Scrum teams now doing 2 week sprints. Or even less. Note: One version of the Nokia Test that I have seen says iterations 6 weeks or less. This is a standard in iterative or Agile, but not in Scrum (which is 30 days (4 weeks) or less).

The iterations are time-boxed. This means that the length of the iteration does not change from iteration to iteration. And we do not extend any single iteration (or sprint) because "we're not quite done yet".

Why are time-boxes important? First, "when a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully." (Samuel Johnson) It is easy for us to get distracted, and the time-box forces the team to face the real world. It forces them to cut through analysis paralysis.

Time-boxes are also wonderful is a slightly different way. You are no doubt familiar with the Pareto principle (aka the 80-20 rule or the law of the vital few). So, the team is forced to choose those "20" most important things to do and get done in that time-box, out of the wonderfully long list of "100" good things to do in their lifetimes.

And, by making the goalposts immovable, the team starts to see that the time-box has meaning. They must estimate better or work better or in some other way improve if they want to complete their work consistently every iteration.

The time-box also enables the team to reflect, on both their work product and on their work methods and approaches. And to get feedback, and make mid-course corrections. This feedback mechanism is not stated specifically in the Nokia Test, but to me the feedback is in there because it is such an important part of Agile and of Scrum.

We will come back to the usefulness of the time-boxed iterations as we discuss other parts of the Nokia Test. While, for the sake of small blog posts, we are looking at each element, it is really when the elements are together that the test starts to have real power or meaning.

The whole is greater than the sum of the parts.

3 comments:

adam said...
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Anonymous said...

What happened to the rest of the series?

Joe Little said...

Hi Anon,

I just got very busy. Let me do one more today.

Thanks, Joe