No job has the same requirements twice. This means no project should have identical resources twice.
Every CM can agree there’s nothing worse than seeing a construction site with workers twiddling their thumbs. The name of the game is having consistent processes that are scalable to a consistent output, regardless of scope. Another important part of tackling work variation is ensuring productivity remains constant. Lean Construction blog points out that “Deviation or fluctuations in the performance of a crew will cause variation and, ultimately, corrupt reliable workflow. The result is workers waiting for work or work waiting for workers, the two biggest forms of waste on a project. One of the fundamental principles of Lean Construction is reducing variation on construction sites.”
The question remains, how can we prepare for anything – whether unusually large or unusually small.
Understanding workflow and its patterns can be an asset in preventing delays or complications. Jeff Esgar, a Lean Construction author, calls out a distinction that is important to make. He separates predictable and reliable workflow into two separate categories. Predictable means events can be figured out before they happen. Reliable is the level to which a plan will always work. With this, he says “Knowing that workflow is reliable shows that we can have a predictable start and release of work.” The challenge is to increase reliability while understanding factors with predictability are inevitable, but also something to be cognizant of.
There are ways to use buffers to reduce the effect of any variations preemptively. Some examples of buffers include size/inventory, capacity, and schedule. By preparing for a job with additional inventory where available on site, this can compensate for a need of additional resources in an easily accessible way. Project managers can utilize capacity to create room to absorb periods of excess demand. Also, creating a schedule buffer can help prevent delay and serve as a “Plan B,” should anything pop up.
One additional practice that should remain a goal is reducing and eliminating variation wherever possible—easier said than done. Through experience however, firms can recognize historical trends and use this to make improvements on how work is executed/planned in the future.
The goal is to gain a flow that withstands any interruption. Although this statement is also a lot easier said than done, by reducing variation wherever possible, there are many less workers either waiting around or under-resourced.
Sources referenced:
http://leanconstructionblog.com/Breaking-Through-the-Variation-Barrier.html