The short answer
The link breaks in a predictable place: the enquiry is recorded with its source, and then the outcome is recorded somewhere else, with no connection between the two.
Carrying an identifier from the form through to the outcome record closes it, and that is most of the work.
Where the chain breaks
| Break | Result |
|---|---|
| Source not captured with the enquiry | No way to attribute anything |
| Enquiry retyped into another system | Source lost in the retyping |
| Outcome recorded elsewhere | Never joined back |
| Phone enquiries | Frequently no source at all |
| Long gap to close | Nobody looks back that far |
Retyping is the most common and the most avoidable. Every manual re-entry is an opportunity for the source to disappear.
What to capture at the form
- The campaign and source parameters from the visit.
- The landing page and the referrer.
- A first-seen timestamp, not just the submission time.
- An identifier that travels with the enquiry.
- Enough detail to recognise the same person later.
Point three is useful for long cycles. Knowing when someone first arrived, not just when they finally enquired, changes which campaign gets credit.
Phone calls need a deliberate answer
- A different number on advertising pages
- Ask callers how they found you, and record it
- Record the answer in the same place as web enquiries
- Accept that the answer is sometimes wrong
- Report phone enquiries separately rather than ignoring them
Ignoring phone enquiries in reporting makes advertising look worse than it is, particularly for services people would rather discuss than type about.
Accept imperfect attribution
Some share of enquiries will never be attributable, and chasing the last fraction costs more than it is worth. Aim for a consistent picture rather than a complete one.
Consistency is what makes the numbers useful. A measure that misses the same proportion each month still shows you direction.