“Work-in-Process” is a fancy name for jobs which are started but not finished. You may have a collection of half-finished projects on your desk, or in your garage, or your sewing area. These are all Work-in-Process or WIP.
At home, we usually realize that it’s not a great idea to have a dozen carpentry projects going at once. The partially-finished projects clutter up the garage. Every time you have a yen for carpentry, you’ve got to decide which project to work on and pull it out of the collection.
At the office, it’s often harder to see the cost of Work-In-Process. Instead of cluttering up a room, our half-finished work is just bits on a disk – much less visible, but still taking time to store and manage.
Worse, work in the office tends to cause much more task-switching than home carpentry projects. Human beings can switch rapidly and easily between some types of tasks, but engineering is not one of them. It can take as much as ten minutes to come up to speed on a task requiring concentrated thought. Each time a worker switches tasks, that “tax” must be paid again, yet people are often expected to switch dozens of times a day. This is an enormous drain on time and energy.
Limiting Work-in-Process can make your department more efficient, and your people happier. The time wasted by task-switching can be recovered by simply changing the order in which work is done. For instance:
- Consolidate work into natural time blocks. Joe works on project A Mondays and Wednesdays, and project B on Tuesdays, Thursdays, and Fridays. Rajesh works on project A in the morning and project B in the afternoon. Email and inquiries from the “other” project must wait its turn.
- Consolidate work across people. If you have four projects spread across four people, try rearranging the work so each person only works on two projects at a time. Some individuals may have to learn additional skills, but that’s often less effort than keeping track of multiple projects (and better for their careers).
- Do projects in sequence rather than all at once. Start two projects, and finish at least one before starting another one. Even though projects are not started immediately, they end sooner than if many projects are running concurrently.
Agile projects already limit WIP implicitly, by accepting only a certain amount of work into the iteration, but you may still have people juggling multiple user stories at the same time. Supporting staff, such as test teams or documentation staff, are often handling multiple projects simultaneously. Anything you can do to limit WIP such that an individual is working on only two or three projects at a time will help.
So that’s why Lean and agile methods limit Work-in-Process. High WIP costs time and money, and it’s hard on the people as well. Lowering WIP is one of the easier ways to make your department more efficient and a better place to work.
Learn more: If you’re working in software, you may appreciate this article by Johanna Rothman: http://www.jrothman.com/2010/01/the-silent-project-killer/