When designing an application or a paper-based form, it’s often necessary to provide an example or use a default value until the user inputs their own data. A couple of recent examples prompted me to think about ways to choose and handle these.

Examples

I recently needed to transfer some money between bank accounts. I used my bank’s generally-excellent online banking system, and found that they had thoughtfully supplied an example amount. I suppose they thought this example would make it clear that the pounds value goes in the first box and the pennies value in the second, but I think they’ve failed here. I’d be interested to see how many people write the complete amount they want to transfer, including pound symbol and decimal point, into the first box.

The other danger of giving examples is that people might feel bound to use that amount. This may seem ridiculous, but stories abound of people doing really stupid things when interacting with computers, not always in proportion to their general intelligence. Remember, half your users will be below average intelligence (for their population, and yes, I do know about mean, median and modal averages).

Felicitously, the amount I needed to transfer was approximately that given in the example, so in the interests of research, I decided to use exactly that value to see what would happen. Given the unlikelihood of someone intending to transfer precisely that amount, it would have been sensible to provide a warning to prevent a momentary lapse of brainpower triggering an unwanted transfer: you have entered the same amount as in our example — are you sure you want to do this? But no, the transfer went through without warning.

Perhaps I’m being over-cautious and underestimating the general online-banking-using public, but I’d like to know how many transfers of £550.57 there have been in relation to other adjacent figures, and whether the bank staff have a chuckle at their idiot customers any time such a transfer goes through.

Default values

We moved house a couple of months ago. Our first water bill turned up yesterday, showing the meter reading we’d provided when we moved in and the new estimated “reading” on which our bill was based. Now, for a new customer, estimating readings presents a problem as there’s no history to draw on — I don’t believe the infrastructure or processes are in place to allow South Staffordshire to contact Essex and Suffolk to find out how many baths we had per week when we lived in their patch.

So, there are a few things they could have done:

• Ask us for a real meter reading. It’s not the easiest to take, as the meter is buried in the drive underneath a metal cover, a foam frost protector and a thick layer of grime, but it’s not impossible and it’d need reading eventually anyway;
• Use past history from the property, assuming the previous occupant was reasonable with water use;
• Use a default value based on the type of property and type of occupancy.

None of these methods will be correct, but any would be better than the value they chose:

That’s right, they decided that the most appropriate guess for the amount of water used by a family of four for a period of 69 days was none at all.

So our options were to pay the bill consisting of standing charges only, and carry over the water use charges until the next real meter reading, or ring up to provide a true meter reading. Surely it would have been better to explicitly ask us for a meter reading (or even send someone round to take it) rather than send out a bill that appeared not to require any action other than payment, but would eventually end up with a steep increase in charges once the payment deficit became clear?

Summary

These two examples are from seemingly competent companies — the online banking system is great and the water bill is nice and clear — but both examples expose potential error states for users not paying close attention.

When creating examples or choosing default values, think very carefully. Assume a distracted user towards the low end of competence at the task you’re asking them to complete. Do your examples help or generate a risk of incorrect data being entered? Are your default values reasonable? Could it be harmful to the user if they chose (deliberately or through inattention) to use the default value rather than explicitly entering data?

I’d love to hear about other instances of potentially-confusing examples or silly default values: comment away below!