Kanban Results

Over the past year our Kanban teams have been striving to reduce the following:

• Lead Time – the time it takes from a customer request to when it is delivered
• Development time – the time it takes from entering the Ready For Development queue to when it is handed off to QA
• Engineering time – the time it takes from entering the Ready For Engineering queue to when it has passed QA, left Engineering, and is ready for UAT

Through various means; working on the system, talking about blockers first in the standup, actively assigning, escalating and removing blockers, recognising and reducing bottlenecks, retrospectives, improving our process by separating common cause problems from special cause problems, using MMFs and component stories and tasks, implementing Kaizen, implementing classes of service, highlighting items that have been on the board for too long, to name but a few, we have seen improved results which are depicted below in Statistical Process Control charts using data taken from our largest Kanban team.

Note the links in the above paragraph link to other areas of this blog that describe in more detail how each of these have been achieved. You can click on each of the charts below to see a larger version.

Lead Time

Lead time has reduced from a mean of 22 days to 14 days over the past year. There is a consistent downward trend with the majority of the most recent items under the mean. Each of the outliers were proved to be special cause. The periods on the charts have been split from 2008 until our financial year end (April 2009), and from July 2009 until October 2009.

Development Time

Development time has reduced from a mean of 9 days to 3 days over the past year.There is a consistent downward trend. This portion of the value stream was directly under the team’s control and not subject to delays from 3rd parties or upstream or downstream parties. The major factor in reducing development time has been to limit work in process. The periods on the charts have been split from 2008 until our financial year end (April 2009), and from July 2009 until October 2009.

Engineering Time

Engineering time has reduced from a mean of 11 days to 8 days over the past year. Once again there is a downward trend. However there are more outliers that required investigation. Some of the outliers were proved to be special cause, but the majority were down to waiting for 3rd parties to complete their development and QA, something the team actively worked on to reduce. The periods on the charts have been split from 2008 until our financial year end (April 2009), and from July 2009 until October 2009.

Throughput

We class throughput as the number of items released, and would expect an upward trend as the code base is decoupled, work items broken into MMFs, and cycle time reduces. The chart below shows this upward trend in the number of releases per month. Note that we are subject to release freezes hence the drop from December to February where the release freezes were imposed.

Bugs Per Week

We need to ensure that the reduction in lead and cycle times, and increase in throughput are not at the expense of quality. The chart below shows that the number of live bugs is within statistical control, and since July we are actually seeing a reduction.

 

There are now several follow on posts from this original post

http://leanandkanban.wordpress.com/2009/10/25/kanban-results-feedback/

http://leanandkanban.wordpress.com/2009/10/26/kanban-results-part-2/