Forms: the strongest case
A form submitted in the same browser session that arrived from an ad can carry everything: the campaign parameters, the click identifier, the landing page, the referrer and the timestamp. Nothing is inferred. This is why campaign reporting always looks best for form-heavy businesses — not because forms produce better leads, but because they produce better records.
The one requirement is that the entry context is held from landing until submission, so a visitor who reads three pages first does not arrive at the form looking anonymous.
Conversational bots: forms with a longer tail
A bot conversation captures the same parameters as a form, with two differences worth planning for. First, the session lasts longer, so the context must persist across several exchanges. Second, a partially completed conversation may still be worth keeping — an abandoned conversation with a phone number and a campaign attached is a real lead with real attribution.
Treat the bot's outcome and its attribution as separate facts: whether the conversation qualified the person, and where the person came from, are different questions.
Calls: inference done carefully
- Dedicated tracked numbers per channel are the strongest available method — the number dialled is the attribution.
- Matching an inbound number to a recent web session is suggestive when the timing is tight, and unreliable when it is not.
- Asking 'how did you hear about us' produces the caller's memory, which is genuinely useful and genuinely unreliable.
- Whatever the method, record which method was used, so a report can separate proof from inference.
Manual entry: label the belief
A rep typing a lead in after a home show, a referral phoned in by an existing customer, a commercial contact from a supplier — all legitimate, none carrying machine evidence. The right treatment is to record it plainly as a manual tag with the person who set it and when.
This costs nothing and pays off during arguments. 'Referral' set by a named person on a known date is a claim you can go and check. 'Referral' appearing in a column with no provenance is folklore.
Reading a mixed report
Once the capture path is stored, a channel report becomes readable in a way it never was before. A campaign with fifty form leads and a campaign with fifty phone leads are not equally proven, and the report should let you see that at a glance before anybody moves a budget.