Ali Demirbaş - Lab

Forms & Signup

One-Column vs Two-Column Form Layout A/B Test

Two-column forms can look shorter but make the reading order less obvious.

  • Forms & signup
  • Form completion rate

Control vs Variant

How the blocks are arranged is the variable.

Changed
Layout
Page
Forms & signup
Difference
changed

Hypothesis

A single column gives a clearer sequence while taking more vertical space. Compare submissions with the same fields and logical order; placing related fields side by side is a separate layout test.

How to run this test

Primary metric

Form completion rate

Compare successful submissions to see whether a single-column layout affects completion.

Other metrics

  • Required-field error rateTrack errors from blank required fields or invalid entries.
  • Form completion timeCompare time from form start to successful submission.
  • Form start rateMeasure visitors who begin entering information after seeing the form.
  • Valid submission rateCompare submissions that pass backend validation; a submit-button click alone is not success.

What to check before and during the test

  • ColumnsMove the same two-column field set into one column.
  • Keep constantKeep logical field order, field widths, copy and validation unchanged.
  • Skipped fieldsCheck whether visitors skip the second column more often in the control.
  • ScopeExclude devices where both arms already use a single column.
  • Separate testKeeping related fields side by side is a separate layout comparison.

Setup mistakes to avoid

  1. 1Do not change layout and field order together.
  2. 2Do not test a two-column variant on mobile where the form already becomes single-column; there is no change to measure.
  3. 3Do not change field width as well as column count.
  4. 4Preserve tab order when repositioning related fields.
  5. 5Do not generalize results across forms of different lengths; a three-field form may behave differently from a twelve-field one.