Thursday, July 07, 2005

Agile Fence Painting

I nearly choked on my sandwich, mid bite, yesterday at lunch. My wife had just said, “You know it really pays to be thorough. All that rework is really time consuming and it uses a lot of paint!” So there was hope after all that my wife might understand what I do for a living.

We have been sealing the perimeter fence at our home. The building is 5 years old. The fence has never been treated since it was new. It was badly needing done and we had purposefully set aside some time at the beginning of July to do the job. The last two days we’ve been “painting” the fence around our house.

So how do you manage a domestic fence painting project? Well the agile way - naturally. You buy some wood stain sealer, some brushes and you start painting. You determine the velocity in fine-grained units of value - in this case, the amount of fence painted, not the hours spent painting it. The finest grain unit available is the plank. However, analyzing how many planks there were, sounded like, big analysis up front, to me. The next unit of granularity is, the fence section - a set of planks between two poles. Easily calculated - 22, in our case. The initial scope was to paint one side of the fence - the side we can see from the house. So we measured velocity after 90 minutes of painting - approximately 3 sections per hour. But we also noticed that some special cause outage was possible - children come and complain about stuff and need attention. So the low end velocity might be 2.5 sections per hour. If we hussle, the high end could be 4 sections per hour. So it should take between 6 and 11 hours to complete the job.

What about the available hours - the load factor? Well , we couldn’t dedicate the whole of the day to the job, so it was likely to take 2 days. What we weren’t to know was that one of our painters was too eager and would paint with poor quality requiring significant rework. This would affect both over all velocity and consumption of raw material.

What about iterative work cycles? Good idea! What value groupings make sensible incremental deliveries? Well the front section of fence, forward of the gate. The bit that can be seen from the street - 6 sections plus a gate - made sense as iteration 1. It was the highest value section, due to its public visibility. The next section at the side of the house (pictured) was another good incremental delivery but of low value. Then the gate and fence at the other side of the house onto the shared driveway. Finally, the fence around the back yard. So 4 incremental deliveries. 4 good “stopping points”. Note: the best value is delivered from appropriate domain specific groupings, not from a regular cadence of, say, 4 hour, sprints. Even though a regular cadence does facilitate the need for a tea break.

So, at the first iteration review - the cup of tea after completing the front section of the fence [Readers from the UK will note that British tradesmen often ask for a cup of tea on arrival at the job before commencing work. This is sure fire sign that you have hired a traditional big planning up-front tradesman, rather than a more nimble, better value, agile tradesman.] - we analyzed the raw material usage - 4 sections of fence per gallon of sealer. Issue: we didn’t have enough sealer to complete the job. So the project manager was dispatched to home depot to procure 2 additional gallons. This was done early enough that the painting team never ran out of paint and were never idle during assigned painting hours.

And finally, it occurs to me that this sealer has a 6 year life span. The next time this job needs done, my 3 year old will be 9 or 10. So it sounds like I can delegate the task, in exchange for pocket money, and sit back on my comfy patio furniture and “manage” the job with a long cool drink in my hand. I wonder whether the agile manager’s daughter will charge by the hour, by the section, or on a fixed price with a guaranteed quality level and delivery date?