Little's Law, redux


In reference to my April newsletter, about the perils of a multi-tasking environment that forces teams to constantly switch activities among multiple projects, a client wrote:

I am a little surprised you didn’t refer to Pull and WIP control more overtly as part of the solution. I know it is production language, but it should work in admin and is a great way to match input/output rates and to keep resources dedicated until a job is done. Also the queues can then be used as indicators of true capacity (vs coordination) opportunities.

I anchored my argument against this kind of multitasking in Little's Law, which demonstrates that the more items in a queue of work (particularly manufacturing or service), the longer the cycle time for that work becomes.

My client is exactly right, however. A push system, where work is foisted upon a department from the outside, by its very nature will lead to overloading a system and exploding lead times. A pull system, where work is taken from a pile of projects by the people doing the work when they're ready for it, ensures that the department matches inputs and outputs for maximum efficiency.

Interestingly, this approach is rare. There's a tendency in the office environment to treat "production" capacity as infinite. Partly this tendency is due to people's willingness to work late into the night or on weekends. Partly this tendency is due to the difficulty of calculating how much time a particular project will take. Inherent in knowledge work is the inability to take a project to completion in a smooth, uninterrupted flow.

Because there are so many interruptions, and because these projects tend to be multi-stage affairs, there's a powerful argument to use more visual management tools and lean/agile development methods. Both will help clarify and make workloads visible, and help to better match capacity to business opportunities. And that results in shorter lead times, happier customers, and less-stressed employees.

 

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