The short answer
Form abandonment is not spread evenly. One or two fields cause most of it, and you cannot guess which without measuring.
Record the last field someone interacted with before leaving, and the pattern becomes obvious quickly.
The usual culprits
| Field | Why people stop |
|---|---|
| Phone number | Expectation of a sales call |
| Company name | Feels irrelevant to an individual |
| Budget | Unknown, or feels like a trap |
| Website address | Strict validation rejecting valid input |
| Long message box | Effort at the wrong moment |
The website field is a specific and common defect. Strict address validation rejects perfectly normal input and gives an error the visitor cannot resolve.
Measure it properly
- Record which fields were focused, in order.
- Record which were completed.
- Record the last field touched when someone leaves without submitting.
- Exclude hidden anti-spam fields from that record.
- Separate mobile from desktop, because the patterns differ.
Point four matters. A hidden field appearing as the last one touched is a measurement artefact and will send you looking in the wrong place.
Validation is a common cause
- Accept addresses with or without the protocol prefix
- Accept phone numbers with spaces, brackets and country codes
- Validate when the field is left, not on every keystroke
- Say what is wrong and what would be right
- Never clear the field on an error
Clearing a field when validation fails is close to guaranteed abandonment, particularly on a phone where retyping is slow.
Remove before you optimise
The fastest improvement is usually deleting a field. For each one, ask what you would do differently if it were empty. If the answer is nothing, it does not need to be there.
Anything genuinely needed later can be asked for in the reply, once someone has a reason to answer.