Demarco’s hypothesis is that not only is slack necessary to improve work performance, it is actually essential for a business’s survival:
Slack at all levels is necessary to make the organization work effectively and to grow. It is the lubricant of change. Good companies excel in the creative use of slack. And bad ones can only obsess about removing it.
For business to survive they need find new ways to reinvent themselves, the need inspiration, they need to be able to change
Slack is the way you invest in change. Slack represents operational capacity sacrificed in the interests of long-term health.
[Failure to reinvent] is often the result of a failure to set aside the resources necessary to let invention happen. The principal resource needed for invention is slack. When companies can’t invent, it’s usually because their people are too damn busy.
Cal Newport (A World Without Emai
l) explores how technology has removed support roles such as admin assistants from workplaces with very negative impacts on productivity,
When you eliminate support staff, the skilled professionals become less intellectually specialized, as they have to spend more time on administrative work that computers made just easy enough for them to handle on their own
Because the professionals have much higher salaries than the support staff, replacing the latter with more of the former can be expensive… the organizations … studied could immediately reduce their staffing costs by 15 percent by hiring more support staff, allowing their professionals to become more productive
Demarco highlights how support staff are often seen as overhead that can be easily removed as Mckinsey come through on the next round of efficiency cuts,
We have become so obsessed with getting rid of people who are burdened with the characterization overhead that we have ended up with organizations where many high-priced knowledge workers and managers are spending as much as a quarter of their time being their own overhead.
The Theory of Constraints
help explain why flow efficiency drops as slack is removed from a system. Production Systems (including knowledge work) naturally have a bottleneck that determines the throughput of the system. You want this bottleneck to be clearly identified so the focus can remain on ensuring that it is operating at capacity. By definition however this means that resources around the bottle will have slack. Frequently the slack is taken advantage of, either by introducing more work that is not helpful to the overall flow of the system (throughput actually goes down as WIP increases!), or resources are removed to “balance the line” creating a situation where the bottleneck might become starved of work from upstream variation, or forced to reduce work output due to limitations downstream.