It’s happened to you, hasn’t it? You try inserting your card at an ATM, gas pump or hotel door, and nothing registers, so you have to keep trying different ways until it works.
And it’s all your fault, isn’t it? For not knowing by now which way to insert it? For not looking at the little pictogram that makes it all clear?
I conducted some quick & dirty product research, asking several supermarket checkout clerks how often customers mis-swipe. The estimates they gave ranged from 1/3rd to 50% error rate, a critically high rate. Since so many people make the error, it’s not your error at all, but a trap built into the system.
What is the problem?
There are two main sources of the problem:
- There are four possible ways to insert a card, but only one way is considered “correct."
- Card readers are inconsistent among themselves. Some have a horizontal slot, some a vertical slot, some a face that you swipe. These different experiences tug the user in different directions, with the training imparted by one device reversed by the next. As a result, one never really get good at inserting the retched card in the retched slot.
Different card readers try to show a diagram of how you’re supposed to hold and insert your card. The best of these show it in perspective, making the mapping from reality to the diagram easier. But these efforts are beside the point. To process instructions, even visually, requires you to halt your conversation, break your train of thought, read and think. This is expecting too much of someone doing a cursory activity.
Some ATMs detect the leading edge of the card and block the card if it’s not going in the right way. This is a bit better, but it still requires experimentation to get right.
Regular keys don’t typically have this problem. Must card keys?
Vision
We need a solution that is as automatic and thoughtless as inserting a regular key into a keyhole. One that doesn’t require you to stop, think, experiment; one that is obvious. Why can’t the slot just accept the card however you insert it?
Possible remedies
Instead of just one solution, let’s show a range of possibilities that might be appropriate depending on the circumstances: whether we need to worry about backwards-compatibility of legacy cards, economic constraints, and so forth:
- Make the shape of the card asymmetric, so there is only one way it can be inserted. (Precedent: the punch card of the 60’s or the SD card of today). The downside is you still have to insert the card before discovering that it’s the wrong way.
- Include two or four magstripe readers in the slot. This makes the machine tolerant of other ways of inserting the card. Two readers reduces the error rate greatly; four readers eliminates it altogehter. No instructions needed![5/26/05 Update: I came across a soda vending machine that allowed bills to be inserted face up, either way]
- Put the stripe down the middle of the card, not against one edge. Have the reader read the information backwards or forwards. Then you only have to insert the card up or down. This solution works if you don’t have to worry about the “installed base” of users. Here’s the before (left) and mocked-up after (right):
- Have a strip in the middle of the card and include two magstripe readers in the reading device. (hybrid of 2 and 3): This allows all four ways of inserting the card, with the lower cost of only two readers.
- Avoid having to insert the card to begin with. There are office doors that require only a wave of a card key across a reader. Prius owners never have to insert a key into the ignition; it just detects your presence through a key fob and lets you open the door and start the car. (But be wary of the unintended consequences of RFIDs.)
Applies to
- Any device that accepts magnetic cards: ATMs, Credit card readers, check-in kiosks in airports, parking ticket kiosks, transit turnstiles, library self-checkout kiosks.
- Vending machines that accept bills
Follow-up Research Topic
For the interaction design researchers or card reader companies: create a prototype card reader which accepts cards in any orientation. Try out different orientations of the reader. Measure the natural ways that people insert the cards to inform the design solution.
(Hypothesis: vertically orientated would have fewer errors than horizontally-oriented readers, because there is a clearer “up”. If so, it reduces the necessity — and cost — of including magstripe readers for two of the orientations.)
How about a design that doesn’t require to redesign the card readers, nor does it require double sided card readers? Could one create a card, that would only make sense being held by a user in only one direction and orientation that would work in vertical and horizontal readers? I am thinking about a card that basically had the look of a thumb indent, so you know where your thumb should go as you swipe the card. Maybe even have this part of the card be thicker so you could have a real indent where the thumb goes. Did you also notice that card readers are for RIGHT handed people. I am a lefty, but can live with this. I am going to do an experiment. I am going to put a oval piece of tape where my thumb should go on the card, and see if that reduces my own error rate. ;->