Why Self-Checkout Doesn't Work

There was an article in today's Wall Street Journal about Kroger, the major grocery chain, and their efforts to reduce waiting time at checkout.

Supermarket giant Kroger Co. is winning the war against lengthy checkout lines with a powerful weapon: infrared cameras long used by the military and law-enforcement to track people.

These cameras, which detect body heat, sit at the entrances and above cash registers at most of Kroger's roughly 2,400 stores. Paired with in-house software that determines the number of lanes that need to be open, the technology has reduced the customer's average wait time to 26 seconds. That compares with an average of four minutes before Kroger began installing the cameras in 2010.

Now, the article goes on to describe how Kroger uses that data, which tracks how customers move through the store, to predict how much staffing they'll need at the registers in half-hour increments.

I took particular interest in the article because I really really don't like waiting in lines.  It's the equivalent of a human traffic jam that'll take some time to clear, increasing the cost (in the form of my time) all so I can have a sandwich or buy toothpaste or get a question answered.

It's not all lines inherently bother me, necessarily.  If I go to a Chipotle at 12:30, I know it'll have a massive line and I know about how long it takes.  Plus, it's clear from the structure of the operations and the attitude of the employees that they're trying to get me through as fast as they humanly can (I'll bet that's even tracked back at HQ).

So, lines are OK if they meet two primary conditions:

 - The wait time is expected/known
 - The business/employees are actively working to make my wait shorter

Of course, for anyone who has shopped at a grocery store, you know that neither of those are necessarily true.

The second condition is rarely seen in practice.  Contrast the furious burrito-making at Chipotle (or the equally furious sandwich making at Subway) with most grocery store checkouts.  It's not always the fastest pace (although some chains have worked to track checkout clerk speed, but I think results have been mixed)

The absence of the first condition is a result of poor planning and inertia, at least with most supermarkets.  You usually have no idea how long you'll wait.

Any recent shopper knows the drill, walk around the checkout area, scanning the aisles for the best slot.  Who has a relatively empty cart?  Which line has the shortest queue?  Which clerk looks like the give the biggest sh*t?

Often these estimates are met with futility.  Like when the woman buying a solitary candy bar whips out a change purse and starts counting (Aside: If you look to make exact change for a purchase, please stop.  You are placing a larger inconvenience on everyone behind you, all so you can get the exact $1.09 for your Three Musketeers.  No one's life is improved by your choice)

The problem is a high degree of variation in service time.  Some customers will unpack their basket as fast as possible, pay with a credit card, and engage in zero extraneous communication.  Others seem to WANT to take as much time as possible.

This creates a problem when you have a dozen discrete lines like a traditional supermarket.  It creates a system that's inherently unfair.  Someone in one line has to wait much longer than someone in another.

Now, at one point supermarkets were pretty sure they figured this out.

Self-Checkout!

The purported saving grace for the busy shopper, the self-checkout was designed to free us all of the tyranny of the lines (or, more accurately, free the supermarkets from the tyranny of hiring and paying employees)

I have to admit, I was smitten when they first rolled out the technology.  You see, having worked in a traditional supermarket in high school, I had a lot of experience bagging groceries.  And I knew that if I could just do it myself, I'd be all that much faster.

Of course, in reality, nothing could be further from the truth.

There are a series of practical realities that preclude self-checkout from ever being a reasonable solution (in its current form)

1 - Random weight items: Self-checkout is simple when the packaging is standardized, you just scan the bar code.  But with any random weight items (i.e., produce), they require a specific ID code, typically 4-5 alphanumeric characters.  Well, if you're an experienced clerk and know them all by heart, that's fine.  But for the rest of us, we're left to stumble through an alphabetical picture book that makes you feel about as smart as a 4 year old.  Find the apple.  Now find the onion.  Now find the broccoli.  It's literally a kindergarten exercise, but one that takes way more time than it otherwise would.

2 - Anti-theft nonsense: Of course, when you allow for 'self' checkout, you're implicitly allowing customers the opportunity the steal from you.  Like a slightly muted version of the honor system, you're giving customers the responsibility to manage their own purchases.  There's a social contract element to that, only the ingenious minds behind the self-checkout couldn't go that far, and put weight scanners in the bagging area, surely so they could ensure that one scan equals one package in the bagging area. 

Of course, whatever testing they had in place didn't do the job.  I have yet to go through a self-checkout that trusts me.  After I scan and bag my item, the machine will request me to put the item in the bagging area.  Caught in a weird catch 22, because I've already bagged it, I'll look confused for a second.  The machine asks again, seemingly growing impatient.  But what can I do machine?  I've already bagged it!!!  By then it's too late, the machine has signaled for an attendant (this is not a machine with compassion.  If it were on the parole board Red would still be wasting away at Shawshank)

This isn't to say that customers don't steal, here's proof.

They just do it in better ways!

3 - Bagging: Self-checkout also means you have to bag groceries yourself.  That's obvious to many people, but I've seen a number of folks roll through self-checkout without really understanding that they'll have to then corral all their stuff and get out the door.  Even for a bagging savant like me, it's no better than a push with the employee equivalent.

4 - Other absurd rules: To buy alcohol, I obviously can't use self-checkout, unless I have a 17 year old grocery clerk come over and verify the fact that I should've stopped buying malt beverages 10+ years ago

Add up all the ridiculous delays and poorly designed mechanisms, and you have a recipe for a LONGER wait time.  Some stores have caught on and are ripping out their self-checkout aisles (I'm sure others found some labor savings in making things more inconvenient for customers, and have stuck with it).

But if a chain really wants to reduce lines, it's honestly not all that complicated.

You need a mechanism that takes the key wait time driver (service time variance), and remove it as a driver.

How do you do that???

By having one line!

Just like airports, which have one line leading to multiple service desks, so too should supermarkets be designed.

Some places I've shopped at (Walgreens and Nordstrom Rack here in Chicago), have actually done this.  And it's much much better.  The one line is longer, but it moves much faster, and I never have to kick myself for getting in line behind someone who barely knows what planet their on.

All supermarkets should shift to this, right???

Well, sure, in a perfect world.  But unfortunately, that would take some investment in moving all the fixtures around.  Supermarkets would also lose out on a lot of valuable high-margin checkout aisle shelves.

And since there aren't really a ton of new supermarkets coming in to compete, there's a bit on an incentive issue...

So it might be a long time before I can comfortably take my place in one giant line at my local supermarket.  But then, I could just order the stuff online...