Engagement
Field completion rate
Also called field fill rate.
Field completion rate is the share of form starts in which a given field received a value. It shows where people stall inside a form.
How it is measured
Count sessions that started the form, then count how many of them filled a specific field. Divide the second by the first, field by field. Optional and prefilled fields need separate treatment.
To measure it without storing what was typed, send a custom event when a field passes validation. The event carries the field name, never the value.
Worked example
A mortgage enquiry form has 11 fields and 1,000 starts. Name is at 96 percent, email 91, phone 58 and income 34. The income field is where nearly two thirds leave.
The lender makes income optional and moves it to the last step. Completed forms rise from 210 to 330.
How it differs
Field completion rate works at the field level. Form abandonment works at the form level. Form analytics is the practice that produces both. A field with a low rate is a candidate for removal or delay.
Common errors
Counting a prefilled field as completed. Ignoring optional fields. Reading rates without start counts. Logging what was typed. Treating browser autofill as effort.
In practice
Take the three lowest fields and ask whether you need each one. Remove or defer one this week.