Labeling Required and Optional Form Fields Test

Form analytics with required fields left blank, visitors who stall on an optional field and leave, or support contacts asking which information is needed are signs that field status in the checkout form is unclear. With clear labels, required-field errors should drop as visitors skip optional fields and submit the form. Match every label to the fields the backend actually requires before launch; if drop-offs come from confusing error messages, look at those first.

Form completion rate

Compare successful submissions among visitors who see the form.

Also track

• Required-field error rateTrack errors caused by missing required fields or invalid entries.
• Form completion timeCompare time from form start to successful submission.
• Field-level abandonmentReview the last field interacted with by visitors who leave without completing the form.
• Form-related support rateTrack support requests about filling in the form or understanding a field.

• LabelsUse one consistent rule to mark each field as required or optional.
• Keep constantKeep field count, order and validation rules unchanged.
• ErrorsTrack errors caused by required fields left blank.
• MobileMake sure labels do not truncate field names on narrow screens.
• Separate comparisonsTest an asterisk versus written labels, or different label placement, separately.

1. 1The form completion rate settles this test. Required-field error rate and field-level abandonment only explain where a difference comes from; if errors fall but the completion rate does not change, that is not enough reason to ship the labels.
2. 2What you measure belongs to the marking rule you tested and this checkout form. Show the labels in the same style as the rest of the form, since a mismatched style makes it hard to tell whether the labels or the visual break caused the difference. Look at mobile and desktop results on their own, and save asterisks versus written labels for a separate test.
3. 3If few visitors see the form, a small difference can take a long time to detect. Before launch, enter today's form completion rate and the relative lift you care about in the sample size calculator; if the sample per variant it returns is large next to the form's traffic, you will not see that effect in a reasonable time. When the gap stays unclear, use form completion time and form-related support rate as context, not as the basis for the decision.