A goal of advertising is to attract new visitors to your website or to generate calls. You don’t want to invest in marketing channels that mainly generate returning visitors or returning calls. Those customers already know you.
With event-tracking all Call Tracking calls can be reported into your Google Analytics account. When a visitor has made a call to a specific Call Tracking number before within 30 days, the call can be reported as a returning call.
For each ‘goal’ you create a measurement in Google Analytics. You can set another goal for returning calls. This way you can tell apart the new calls from the returning calls and only invest in marketing channels that generate new calls.