If you’re wary of operations management, the title of this post might sound like just what’s wrong with business these days: customers shouldn’t be treated like anything but people, right? Do you really want to start thinking of them as numbers? Businesses that do that are quite diabolical!

One thing you might have noticed is that banks that say, “To us you’re more than a number” still assign you a number. There’s a truth to the impersonal view of customers that you can’t always ignore. Sometimes you have to see water, not as the soothing, cooling substance of life, but as two hydrogen atoms bound to one of oxygen. Sometimes you even have to see the phases of the moon not as the constant inconstancy of the queen of the night but as the obstruction of sunlight by the mass of our planet. These perspectives are unromantic taken by themselves, but they are integral parts of the supremely romantic operation of human science.

In the same way, understanding the customer as a flow unit of inventory is integral to the fine-tuned performance of your operation. But what does that mean? A flow unit is anything that enters the complex system of your operation and to which your resources are committed for a period of time. Something like “air” is not a flow unit, even though it comes in and out of your store, because it doesn’t require the commitment of any resources. Most employees with appropriate training can work and breathe at the same time. But products, components, ingredients, and cash are all things that require some handling in order to flow through the store. And so are customers. So it makes sense to track and control the processing times (the time each resource is committed to a flow unit) related to customers, just as you would for those related to your products.

You wouldn’t want to think about customers this way all the time. (Certainly not when you’re actually dealing with them!) You want to keep it covert. The beauty of good retail operations management is that it standardizes efficient practices ahead of time, so that you and your staff don’t have to worry about them while the customer is in the store.