By joining the two kanbans together, we get the build-measure-learn kanban.
Figure 5: The combined build-measure-learn kanban board
The Thousand-foot Views
I had the image of this long kanban board in my head while reading Eric Ries’ book, and when I reached pages 138-139, I found a kanban diagram right there, with four columns: backlog, in process, built, and validated. There were WIP limits on “in process” and “built,” and the author not only explained how pull and WIP limits work but also showed how to use them to create tension leading to a continuous-improvement culture or kaizen. This knowledge was not available to us in 2005, and our startup never took those steps.
The build-measure-learn loop is a 40,000-foot view. It is a simple diagram that may be sufficient to inform a non-technical company founder. Everybody else at the company needs not only to understand Eric Ries’ kanban diagram but also to get more detailed views from 30,000 feet and down. The long build-measure-learn kanban diagram from the previous section shows an example from one particular company of what a 30,000-foot view may look like. Build, measure, and learn should not be viewed as atomic steps, because a variety of activities informing the lean startup practitioner may be discovered behind those labels.
Optimizing for Response Time
Having the new build-measure-learn kanban board in front of us, we must ask ourselves: What is our optimization goal? For the lean startup, the optimization goal is definitely the response time. Why? Remember, the “product” here is not the product itself, but the validated learning (principle 3). The consumers of validated learning are the founders or venture capitalists. They want to discover their next pivot point as soon as possible. They don’t care as much about throughput (the rate of accumulation of validated learning), as they do for the key bits of validated learning that lead them to the next pivot point. Therefore, the response time is king.