Does a narrower homepage form with step instructions lift conversion?

Our desktop homepage form sat in a wide container, without the step instructions used on mobile. We tested those instructions with a narrower form, at 800px and 680px. Over 15 days, conversion fell 7.6% and 2.6%, short of our confidence bar.

Not significant Desktop 15 days Not called

SURFACE

Homepage

DEVICE

Desktop

VERTICAL

Ecommerce (B2C)

PRIMARY METRIC

Conversion rate

VARIATIONS

2

The hypothesis

By adding clear step instructions and narrowing the desktop form for focus, we will make the next step obvious, resulting in more registration starts.

Step instructions had helped on the mobile form. On desktop, the form sat in a wide container, so we tested whether a narrower, more focused form with the same instructions would help, at 2 widths.

What we changed

Mobile step instructions and a narrower form, at 2 widths

Both versions added the step instructions from the mobile form and narrowed the registration form to focus attention on it. Var A set the container at 800px. Var B set it at 680px.

VAR A: INSTRUCTION + FOCUS (800PX)

Step instructions from the mobile form
Narrower registration form
Container set to 800px

VAR B: INSTRUCTION + FOCUS (680PX)

Step instructions from the mobile form
Narrower registration form
Container set to 680px

The result

Conversion fell 7.6% and 2.6%, short of our confidence bar

CONVERSION RATE

-7.6%

VAR B CONVERSION

-2.6%

Over 15 days, the 800px version (Var A) converted 7.6% worse than the original, and the 680px version (Var B) converted 2.6% worse. Neither gap reached our confidence bar, but both trailed from the start of the test, so we paused it.

What we would do next

Keep the original width and test the order of the questions

Narrowing the form did not help desktop visitors, even with the instructions that worked on mobile. The next test kept the original layout and changed the order of the questions, asking for vehicle details before the service type.