Attributing phone calls to ad clicks

The three ways the industry does it

1. Per-visitor number pools. A script gives each website visitor a number from a pool and remembers the visitor’s source, landing page and click ID. When that number rings, the call is joined to the visit. This is the standard approach for call-tracking platforms. It only covers calls that follow a web visit; see how DNI works.

2. Click IDs. Ad platforms add an identifier to the landing page URL when someone clicks, such as Google’s gclid. A tracking system captures it, holds it with the visit, and attaches it to the call. It can then send the call back to the platform as a conversion, so the platform learns which clicks lead to calls. Which fields are captured, and where they go, differ by provider.

3. Platform-native call reporting. The ad platform does the tracking itself. In Google Ads, when call reporting is on, Google shows a Google forwarding number in call assets and, with a snippet, on your website. The call is routed to your real number, and Google reports details such as time, duration, campaign and ad group. For website calls, the number is swapped dynamically after a click, and a call counts as a conversion if it lasts longer than the minimum length you set. Google states that these numbers belong to Google and can change.

First touch and last touch

A buyer may see a social ad on Monday, search on Wednesday and call from the website on Friday. Attribution has to pick a credit rule.

• First touch credits the source that introduced the person.
• Last touch credits the source active at the moment of the call.

Call tracking is naturally last touch: it sees which number was dialed, and that number reflects where the caller was when they picked up the phone. That tends to favor branded and website sources and to undercount awareness ads. Keep this in mind when you compare a social campaign with a search campaign. See the glossary entry on first touch vs last touch.

What VereTel does: attribution by number

VereTel attributes a call to the tracking number that was dialed. Each number carries a source label, so every call in your desk shows the number and label. For your website, numbers are assigned per site and per page. VereTel does not capture click IDs or UTM values in its reports, does not assign numbers per visitor, does not attribute by keyword, and does not send calls back to ad platforms as conversions. There are no reports today beyond the call list and its filters.

If per-visitor or keyword-level attribution is essential to how you buy media, say so before you choose a plan, because another provider may suit you better.

Designing campaigns so a number is enough

Per-number attribution is precise when you make each number mean one thing. That is a planning task you do once.

1. One number per channel at minimum. Google search, social ads, mail and your organic website should not share a number.
2. One landing page per campaign. If your ACA and Medicare campaigns both send people to the same page, you cannot separate their calls. Give each its own page, and map each page to its own number.
3. Use static numbers where the ad carries the number. Call-only ads, mail, print and directory listings each get a fixed number.
4. Keep your default number for everything else. Direct and unattributed website traffic then shows up in one clearly labeled place.
5. Label numbers by decision, not by detail. “Google Ads · ACA” is useful. “Campaign 14 ad group B” is a maintenance burden you will not keep up.

With that structure, a weekly comparison of calls per number lines up with the decisions you make: keep, cut or add budget by campaign. To turn calls into money, follow measuring cost per call, and see Google Ads call tracking for a worked set-up.