Human capacity is hard to understand, so we create metaphors to simplify things. When people talk about capacity, thought-bubbles emerge from the heads of some managers, revealing an interesting problem. They view capacity as a bucket into which you pour liquid-work until it is full. This metaphor for capacity leads to bad outcomes. Work isn’t like water; and people aren’t like buckets. Modern work is typically hard and oddly shaped. There is no way to plan work that will perfectly tessellate in order to fill every available cubic centimetre inside a bucket, so even if you knew the exact volume of each of these oddly shaped chunks you couldn’t simply add work using the formula:
bucket capacity minus chunk volume equals remaining capacity.
b – c ≠ r
The fact that throwing these clods of knowledge work into a bucket results in gaps is a good thing™. This is called slack and without it effective knowledge work isn’t possible. You can read more about slack in Slack: Getting Past Burnout, Busywork, and the Myth of Total Efficiency.
Now we have to throw out the bucket and move on to the humble soap dispenser.
When you first open a new soap dispenser (the kind with a handy pump) you need to perform some actions to get it started. Usually a twist of the top and a few pumps to prime the tubes. This is called ramping up by many people. Once everything is working as expected, you can easily squirt soap out whenever you want to wash your hands. If the soap runs out, though, you’ll notice that people perform strange frantic pumping actions to try and get a tiny bit of soap out. They know that they should simply refill the soap, but for some reason it is just easier to pump harder on the mechanism – even though the output for this strenuous pounding is nowhere near the amount of soap required to actually clean your hands.
It doesn’t matter too much if you do this to your soap dispenser. We can all admit that we have done this at some point. When you scale this example up to the size of a team of humans, though, you need to stop. Frantically pumping a team to try and get just a tiny squirt of extra output is not a long term strategy for success. If anything, you should be trying to ensure everyone finishes every day with something left in the tank. In the Agile Manifesto, this is referred to as a sustainable pace; you need to ensure that all your pumps deliver a similar amount of soap consistently across the long term.
More importantly, if people go home with energy in the tank – they are available to moments of inspiration. We all know that problems are solved in the bath, or even in dreams… so protecting the capacity for these eureka moments is one of the fundamental missions of management.
The soap dispenser is a metaphor about humans having a finite amount of energy to deploy, rather than the bucket metaphor’s empty capacity. Humans are self-refilling, but everyone has a different recovery rate. When the soap dispenser is empty, you may be able to squeeze out a few final drops of soap by applying pressure; but the outcomes won’t be good because there isn’t enough soap to properly clean your hands.
I said people aren’t like buckets. They aren’t entirely like soap dispensers either; but the way people pump people vigorously to try and squeeze more out of them is a common problem.