How Do You Track Which Marketing Campaigns Actually Generate Quality Calls?

Many businesses track clicks, impressions, and website leads, but it can be harder to understand what happens after someone picks up the phone.

How are you currently connecting the dots between:

Campaign → Call → Lead → Revenue

Do you track which campaigns generate the most calls, which calls turn into qualified leads, or which sources ultimately contribute to revenue?

Curious to hear how others are measuring call-driven marketing performance and what challenges you’ve faced.