This option works similarly to landing page campaign attribution. But instead of analyzing the whole URL, the script looks for a specific URL parameter (utm_source, for instance). If the parameter is found, and the value matches the configured value, the page’s phone number will be swapped. This is a great option for users advertising on multiple sites (Google, Facebook, Instagram, etc) and wanting to see which source is generating the most inbound calls.

To set up a campaign with this method, select the “Numbers” category from the column on the left side of the online portal. 

Scroll down and expand the "Campaign Attribution" section and toggle it on. 

In the upper left box you will then enter the "Target Phone Number" (the number you wish to replace on your website). The box on the upper right is a drop-down where you select the campaign strategy you would like to use for your toll-free number. 

Select "URL Parameter (E.G. UTM_Source)" from the drop-down and then paste or type the specifications in the box on the bottom left labelled "Parameter and Value." The box provides and example of utm_campaign=my-campaign. 

There are 5 parameters you can add to your URLs:

utm_source: Identify the advertiser, site, publication, etc. that is sending traffic to your property, for example: google, newsletter4, billboard.
utm_medium: The advertising or marketing medium, for example: cpc, banner, email newsletter.
utm_campaign: The individual campaign name, slogan, promo code, etc. for a product.
utm_term: Identify paid search keywords. If you're manually tagging paid keyword campaigns, you should also use utm_term to specify the keyword.
utm_content: Used to differentiate similar content, or links within the same ad. For example, if you have two call-to-action links within the same email message, you can use utm_content and set different values for each so you can tell which version is more effective.
Each parameter must be paired with a value that you assign. Each parameter-value pair then contains campaign-related information.

For example, you might use the following parameter-value pairs for your Summer Sale campaign:

utm_source = summer-mailer to identify traffic that results from a summer Sale email campaign
utm_medium = email to identify traffic from the email campaign vs. the in-app campaign
utm_campaign = summer-sale to identify the overall campaign
If you used these parameters, your custom-campaign URL would be:

https://www.example.com/?utm_source=summer-mailer&utm_medium=email&utm_campaign=summer-sale

*When you add parameters to a URL, you should always use utm_source, utm_medium, and utm_campaign, whereas utm_term and utm_content are optional. 

Be sure to click "Save" when finished.

*It is important to note that when using campaign attribution, all the linked numbers will fall under the "tracking numbers" category instead of the "numbers" category within the user interface.