Does zip code autofill lift conversion on a homepage form?
The desktop homepage opened with a short form that asked visitors to type in their zip code. We tested filling it in for them based on their location. Conversion rose 8.9% over 9 days, but the test was paused before it could be called.
Not significant Desktop 9 days Not called
The hypothesis
By filling in the zip code from the visitor's location, we will cut the effort needed to start the form, resulting in more visitors reaching the confirmation step.
The homepage form is the first step of the order, so every field is a small hurdle before the visitor sees any value. The zip code is the only field we can fill in for most visitors without asking, based on their location.
This test was part of a round focused on cutting effort in the first steps of the funnel. The same change ran as a separate mobile test at the same time.
What we changed
The zip code field arrived filled in from the visitor's location.
In the control, visitors typed their zip code into the homepage form themselves. In Var A, we looked up the zip code from the visitor's location and placed it in the field before they reached it. Nothing else on the page or in the form changed.
- Zip code filled in from the visitor's location
- Rest of the form and page unchanged
The result
Conversion rose 8.9% in 9 days, short of a call.
Var A lifted conversion 8.9% over control, and the lift held at each step of the funnel, so the filled-in field did not confuse anyone. Revenue per visitor barely moved, at +0.4%. We planned a full 14 days but paused at 9 days to start the next round of tests, and the result never reached our confidence bar.
The same change on mobile showed too small a lift to call. The change was not implemented.
What we would do next
Rerun it for the full 14 days before judging the lift.
The lift was steady through every step of the funnel, which points to a real drop in effort. But 9 days was too short to trust it, and flat revenue per visitor meant the extra orders were not adding value yet. We would rerun it for the full 14 days, alongside other fields we can fill in for the visitor.