Last December, I wrote about a nice simulation exercise that can be done in a small group to demonstrate the difference between waterfall, lean and agile approches to work. I have now run this exercise approximately 40 times and I would like to share the results.
I should note that these results are eyeball statistics, not carefully tracked statistics.
For Round One, using a waterfall large-batch approach to processing pennies, the results are such that the first and all pennies are completed simultaneously. Typically, the processing time is as follows:
1st Done: 55-65 seconds
All Done: 55-65 seconds
Once in a while there are outliers on the long side: up to 130 seconds. This is usually caused by a team member misunderstanding the instructions or making a large error e.g. dropping all the pennies.
For Round Two, using a lean production line with small batches, the results are substantially better for all the pennies being completed, and much much better for the completion of the first penny. This corresponds to the early and continuous delivery of value that working in small batches can enable. The processing time is typically as follows:
1st Done: 4-8 seconds
All Done: 25-35 seconds
People in my courses are usually astonished by this difference. But it gets even better.
For Round Three, using an agile team working simultaneously on all stages of the penny processing, the gains continue, particularly in how quickly all the pennies are processed. These excellent processing times are as follows:
1st Done: 3-5 seconds
All Done: 15-20 seconds
Although proportionally, this isn’t as big an improvement as that between rounds one and two, it is still a substantial change.
Usually in discussing this exercise, the group is concerned that processing pennies is nothing like developing software, managing a business, etc. because there is so much knowledge and skill required to do these real-world things.
Although this concern is legitimate, nevertheless, my own real-world experience confirms that these levels of improvement are possible. One large organization that I worked with has tracked many projects using waterfall, lean and agile approaches and has observed these types of improvements in terms of initial delivery of finished work, and final delivery of all scheduled work.