Sometimes it is not possible to measure the success of a Google Ads campaign that is aggregated across multiple channels, as is the case with measuring brand awareness and brand favorability. Why is it difficult to determine performance across multiple channels?

• Multiple channels survey only ad-exposed groups of users.
• Multiple channels aggregate all your data into a single view.
• Multiple channels consolidate campaign data for actionable insights.
• Multiple channels may use different tools to measure brand lift.

Sometimes it is not possible to measure the success of a Google Ads campaign that is aggregated across multiple channels, as is the case with measuring brand awareness and brand favorability. Why is it difficult to determine performance across multiple channels?