Centered vs Left-Aligned Form Layout A/B Test

Form completion rate

Compare successful submissions to see whether alignment affects completion.

• Form start rateMeasure visitors who begin the first field after seeing the form.
• Form completion timeCompare time from form start to successful submission.
• Supporting-content click-through rateTrack visitors who open explanatory or reassurance content; an open does not prove it was read.
• Page exit rateCompare page exits among visitors assigned to the form.

• AlignmentCompare left- and center-aligned forms on the same page.
• ContentKeep explanations, reassurance and summary information accessible in both arms.
• DimensionsKeep form width, fields and validation unchanged.
• DeviceExclude device layouts where both arms look the same.
• Separate testRemoving support content or changing form width is a separate test.

1. 1Do not change alignment and form width together.
2. 2Do not quietly remove adjacent reassurance content in the centered layout; test that separately.
3. 3Do not report a mobile lift where the layouts are identical.
4. 4Do not vertically pin the centered form in a way that prevents scrolling.
5. 5Do not generalize results from one page to forms with different purposes.