# Modal Form vs In-Page Form A/B Test Example

Page: https://alidemirbas.com.tr/en/lab/ab-test-library/tests/modal-form-vs-in-page-form-ab-test-example

## Hypothesis

If the form is short and the task fits its context, a modal may gather attention on the form and earn more submissions than the inline version. If the task requires looking at the information behind it, the inline form could pull ahead on form completion rate because it keeps that context visible.

## When to run this test

Heatmaps where few visitors scroll down to the form, session recordings of people passing over it, or visitors who leave the form halfway to go back to the page's explanation show that the form gets overlooked or that visitors need the information behind it while they fill it in. The expected behavior is that the better presentation draws more intentional interaction with the form and more completed submissions. Launch the modal arm only with a visible close button, keyboard dismissal and a trigger rule written down in advance; if the problem lies in the fields or validation, fix that first.

## Primary metric

**Form completion rate**: Assign eligible visitors before they see either presentation and compare successful submissions.

## Other metrics

- **Form start rate**: Measure intentional first interaction with the form the same way in both arms, not modal opens.
- **Data loss after modal dismissal**: This diagnostic exists only in the modal arm; do not compare it directly across arms.
- **Page exit rate**: Compare page exits among visitors assigned to each form presentation.

## What to check before and during the test

- **Presentation**: Show the same form inline in the page or in a modal.
- **Keep constant**: Keep fields, validation and support information the same; define when the modal opens before launch.
- **Data persistence**: Check whether entered information is preserved when the modal is closed and reopened.
- **Browser behavior**: Verify the browser back button behaves as expected in both presentations.
- **Accessibility and device**: Check keyboard dismissal, focus containment and usability on small screens.

## What to watch when reading the result

- Compare form completion rate across all eligible assigned visitors, including those who never open the modal. Data loss after modal dismissal is a diagnostic that exists only in the modal arm; a modal that silently wipes entered data on an outside click is not a winner, however many submissions it collects.
- Count a form start as the first intentional interaction with the form, not as a modal open. Do not weigh a modal squeezed into half of a mobile screen against a desktop result; read each device in its own layout. Treat the outcome as specific to this form on this page.
- Backdrop darkness and the trigger rule must stay fixed for the whole test; if either changed, the result no longer measures presentation alone. Because visitors are assigned before they see either presentation, confirm the arms match the planned split, then compare the two presentations' form completion rates in the [A/B test significance calculator](https://alidemirbas.com.tr/en/calculators/ab-test). Should the gap remain unclear, choose by task length and how much context the form needs.

## Frequently Asked Questions

### Should visitors who never open the modal be included?

Yes. Assign before exposure and compare submissions across all eligible assigned visitors. Selecting modal openers creates a different population from the inline-form arm.

### What counts as a form start in the modal arm?

Count intentional interaction with the form, not opening the modal. Modal-only dismissal or data-loss measures are diagnostics, not directly equivalent control-arm outcomes.

### What should be checked before launching a modal form?

Verify data persistence, browser-back behavior, keyboard dismissal and focus containment. Keep it usable on small screens and provide an accessible close control.

### When might a modal be preferable to an inline form?

A short contextual task may suit a modal. Longer explanations or many fields may suit the inline form. Use form completion as the primary outcome and hold backdrop intensity fixed.