Our local Wal-Mart just installed self-checkout lanes. I know these have been around for a while (I used one in Nashville several years ago), but I hadn’t seen any in Oklahoma until another Wal-Mart, slightly farther away, installed them just before Christmas. I’ve been using whatever excuse I could to go to the self-checkout store, but now I don’t have to anymore.

I love self-checkout. It’s faster for me, and less wasteful: I can fit about twice as much in each bag as their checkers do.

The way they’ve implemented this system has it’s good and bad points, and I’d like to explore that briefly.

(And, yes, I do realize that shopping at Wal-Mart makes baby Jesus cry. I’m supporting a company whose business practices are causing the downfall of civilization. That’s one of those internal conflicts I’ve learned to live with. Besides, today’s topic is usability, not economics, so let’s try to stay focused, shall we?)

For those who’ve never used such a system, here’s how it works: The checkouts are installed in groups of four. There is one checker at the front of this group that is watching to help people having problems. Step up to the machine, put your stuff on the conveyor belt, use the touch screen to tell it what language you speak, then start dragging your items across the scanner. The scanner is a scale, and the display allows you to lookup produce to tell the system what fruits or vegetables you just put on the scale. A motion detector registers when you put something in a bag. If it thinks you put something in the bag without scanning it, it lets you know. The bags themselves are also on a scale. Wal-Mart has apparently weighed every single item in their store, and the system alerts you if the item you put in the bag is the wrong weight for the item scanned.

Those two verification systems are where the problems occur. Nearly every time it tells me I’ve put something in the bag that wasn’t scanned, right after I scanned it. Or it says the item is the wrong weight. I’m not sure what they need to do to fix this, but the system does need to be tweaked.

But, here’s what makes it such a great system: Even when you get an error, it lets you keep going. It may flash its light to alert the checker, but it will allow you to keep scanning items, and even checkout and leave if the checker never comes over to investigate what happened. That’s what makes it usable. That must have been a deliberate design decision: keep the line moving, no matter what. It’s brilliant, because it puts the needs of the customer ahead of the company. They may lose some products because of that, but I believe they will make that up by being able to conveniently process more people than ever before. I just hope the first time they find a bag of M&Ms missing they don’t freak and shut the whole thing down.

The other good thing about this system is it most likely will not cost checkers their jobs. Your average Wal-Mart has, what, about 50 checkouts? At their busiest, I don’t believe they open more than a dozen. With the self-checkout lines, they can probably have twice as many lines available (because you still need checker lines, for the people who don’t like self checkout) with the same number of checkers. People will be able to get out faster, and the dreaded “Wal-Mart trip” will become more convenient.

That is, until the government steps in and shuts them down for monopolistic practices.

I strayed off-topic a bit, didn’t I? Sorry.