Eric recently set up a Google Display Ad campaign. Although, by default, he sees a CPA of $20 in the account, the actual CPA he's using to measure success is $15. What's contributing to the $5 difference?

The lower success metric is caused by view-through conversions, which count people who saw the ad, did not interact with it, and later converted. In Google Ads, these conversions are not included in the main Conversions column for most campaigns, but they do appear in View-through conversions and All conversions. When those additional conversions are included in the calculation, the total number of conversions rises while spend stays the same, so CPA becomes lower. That reporting difference explains why the account can show $20 by default while the success metric shows $15