Why You Should Limit “Work in Progress”
Sometimes I sit down at the end of a day or even a week and am dismayed that I don’t seem to have really accomplished anything. I know I was very busy and I know I was working hard on important things, but why don’t I have anything to show for it?
This scenario is as common for teams as it is for individuals. Most of the time the underlying problem is excessive Work In Progress, or WIP. WIP is anything that you have started but not yet completed. Code waiting for testing is WIP. A design you have “finished” but need approval for is WIP. A requirement you have started to look at but don’t yet understand is WIP.
Excessive WIP is bad for three important reasons. First, it exhausts us mentally. Anything I have started but not finished occupies some part of my available mental capacity. The more WIP, the more my mental energy is consumed with trying to keep track of it all. Add to that the time and energy lost in context switching and the add burden of WIP can become overwhelming.
Second, excessive WIP leads us down the garden path of mistaking activity for accomplishment. When we have a near infinite stream of things to work on and the task at hand bogs down, needs help from elsewhere, becomes unclear, or otherwise becomes “blocked”, we can easily set it aside and pick up something else to work on.
So what is wrong with that? Presumably, the thing we were working on has some measure of importance; otherwise we wouldn’t have been working on it. When we set it aside we make an implicit prioritization that whatever I am going to work on instead is now more important. Of course we probably didn’t think of it that way. We more likely thought, “I can’t just sit around, I need to be busy” and so, rather than exert ourselves to get our original task moving forward we can just set it aside and move on to something else. We focus on being “busy”, not on accomplishing valuable work.
Finally, excess WIP hides process problems and other wastes lurking in our system. I adapted this picture from similar images used to show the undesirable effect of excess inventory in manufacturing. For us, and WIP represents inventory. It is partially completed work sitting around waiting to be finished.
The water is our WIP. When we have plenty of WIP, plenty of other work we can switch to, the rocks below the surface remain undetected. It is only by limiting our WIP (lowering the water level), that we can detect the wastes that are taking up our time and resources. When I first saw a picture like this it didn’t make sense to me. Why lower the water level to the point that you start hitting the rocks? Seems like a bad plan! But the truth is that the “rocks” are lurking down there, robbing us of time and energy. Perhaps more importantly, they are creating whirlpools and rip currents that are keeping us from being productive. We are expending a lot of energy being busy, but we are not really getting anywhere.
If we get serious about limiting our work in progress we will be able to identify and address the impediments to a smooth flow of work and increase our productivity while likely decreasing our business. When in doubt: Stop starting things and start finishing things!