Usability of Codes, Passwords, Numbers, and Letters

Poor usability of codes encountered in website shopping, purchasing, and product delivery is a common complaint voiced by consumers. As evidenced in our testing labs, users experience confusion due to unclear coupon codes, confirmation codes, tracking codes, and passwords. Several questions often asked are…

• Is that a letter or a number?
• Is the code case sensitive?

Below are some examples of codes that might cause difficulty. The first screenshot is an email receipt received after paying a bill online. The second screenshot displays the username and password provided on a scratch-off wireless Internet access card. The issues presented by these codes are that one might not be confident in whether the ‘0' listed in the ‘Approval #’ represents the number ‘0' or the letter ‘O’. Additionally, the ‘1' in the ‘Username’ fields could be mistaken for a lowercase ‘l’ (L)

Image 1: Email Receipt

Image 2: Access Code

Fortunately, providing customers with usable and clearly identifiable codes and passwords can be simplified by following these guidelines:

• Avoid letters and numbers that may cause confusion, such as the lower case ‘l’ (L) and the number ‘1', the upper case ‘O’ and the number ‘0', or the number ‘8’ and the upper case ‘B’.
• If specific letters or numbers are required, use the case of the letter that is easily distinguished. For example, you may choose to use a lower case ‘d’ instead of an upper case ‘D’ because the upper case ‘D’ can sometimes be confused with the upper case ‘O’ or the number ‘0'.
• If possible, always present the number zero as ‘Ø’ instead of an ‘0' to avoid confusion.

In summary, following these guidelines will allow users to use codes more easily and with less frustration, which will create a more pleasant shopping experience that encourages customers to return to your site.

Author: Katie Mauck, Usability Analyst