It's a little disappointing, really. I really thought I was being so smart and creative. I read Pete Abilla's recent post about Little's Law, software development, and queue management, and I thought -- "Hey! I bet you could apply this concept to argue against multitasking and overloading one's calendar! Little's Law proves that if you do that, it will actually take longer to get your work done!"
And then I realized that Pete had beaten me to this flash of insight by, oh, about three years. There it is, in semi-permanent electrons, back in April of 2007:
A common result for multi-taskers is that simultaneous projects or items are spawned. Multi-threaded is sometimes the analogy here. But, unlike machines, people have a difficult time completing multi-threaded processes. The end result is that projects and efforts are not complete, time runs shorter and shorter, and demands continue to pile up. Think of everything I’ve just described as Work-in-Process (WIP). So, using Little’s Law above, as WIP grows, then Throughput decreases. Translation: As we multi-task, we start several projects, complete only a few, WIP grows, Cycle Time eventually lengthens, and we are less productive.
(By the way, although this is the money quote, the whole post is worth reading. He's far more eloquent on Little's Law than I ever could be. Plus, I can't figure out how to insert the Greek letter Lambda in a blog post.)
I think that Pete's point makes a good case for using a tool like a kanban or your calendar to manage the amount of work you take on. If you don't match your production capacity (which is to say, the limits on your time and attention) with the amount of work you take on, you've got a recipe for stress and slower work.
Jim Benson, over at Personal Kanban (where "It's hip to limit your WIP."), tells this story beautifully in his "Personal Kanban 101" Slideshare presentation. The picture above (from that presentation) makes Pete Abilla's point about Little's Law visual.
Jim's point is that the motorcyclist is the last, little, five minute task that you agreed to do. . . but of course, in a completely clogged day, it can't get done quickly at all. And a kanban (his solution), or rigorous use of the calendar (my solution, so far) is a way to ensure that you don't get yourself into this situation -- where five minute tasks can't get done, where the cycle time for your work lengthens, where frustration and unfulfilled promises mount.
Okay, so my idea about Little's Law and multitasking wasn't original. I stand on the shoulders of giants, and all that. But if it brings a bit more attention to Pete Abilla's orginal post, so much the better.