Last Saturday I decided to clean our cars, both mine and my wife's. They really needed cleaning. A few days before I bought a nice, industry-grade vacuum cleaner, better suited for this job than the one we use at home. Basic set of tasks that I have to work through to clean a car is this:
- vacuum the car
- take out foot pads and clean them with water and a detergent
- clean the inner sides of windows
- clean the cockpit with a special detergent so that it looks glossy
The weather on that day was not bad, though pretty windy and when I was about half way through the job, it looked like it was going to rain.
What is the best way to complete as much cleaning as possible, if there is the risk of rain? Should I vacuum both cars first, because I already have the vacuum cleaner running? But would anybody consider a car that has been vacuumed, but still has lots of dust on the cockpit clean? I wouldn't and, what's more, my wife certainly wouldn't either. What is the best way then, again, to achieve the most value during the job of cleaning the cars when it might start raining any minute? Clean the cars one by one, complete all the tasks for one of them and then start another. Then, even if it starts raining when I work on the second car, I will have at least one car completely clean. Even more value could be achieved, if I chose the right car as first to be cleaned and I think you already know which I would choose to gain the most value...
The same thing is with implementing Agile and working within Scrum framework. This actually also shows that Scrum and Kanban are not that far from each other as we sometimes think. In an iteration, it is always best to keep WIP (Work In Progress) strictly limited. It does not make sense for 6 developers to start working on 6 user stories at the beginning of an iteration and finish their work at the end. Ideally, they would all work on one user story at a time, completing one after another. In practice, there will often be some overlap and the team will work on two, sometimes maybe three user stories concurrently, but they must not work on many at once and those that are in-progress at the same time should not be at the same stage (i.e. second user story will often be started when first is nearing completion).
This is what I often advise the teams I work with. Don't start all your user stories at once. Start one, maybe two or three at most. I prefer going to a sprint review at which I learn that 2 of 6 user stories have not been started, than to one where I learn that 3 of 6 user stories are half-done.