date published : May 06, 2015

Have you ever filled out a form and froze on the address field? A research study found that users come to a confusing stop when they encounter the “address line 2” field.


Not only that, but the second address field also caused them to split their input incorrectly in the address fields. This led to confusion and frustration among users.

Labeling the second address field “Apartment/Suite/Other” did not resolve the issue. Users still came to a confusing stop and wondered whether the field was relevant for them.

Familiarity Principle

Having two address fields violates the principle of Familiarity that states the system should match the user’s real world expectations. When there’s a match, users can interpret the interface based on conventions they’re already familiar with.

The second address field forces the user to type their address in the system’s preferred format, not the user’s. In the real world, users think of addresses as a single entity. Two text fields causes them to perceive their address as separate entities. Users don’t expect to see this which is why they get confused.

Real World Expectations

It’s important to design your form based on the user’s real world expectations. If you force users to rethink conventions in order to match the system, you’ll confuse and frustrate them. Don’t force the user to follow the system, force the system to follow the user.