In order to optimize toward customer acquisition, an advertiser should identify keywords with the highest --- ?

To optimize for customer acquisition, an advertiser should prioritize keywords that drive the highest percentage of new-to-brand orders. This metric directly indicates how effectively a keyword is bringing in new customers rather than just capturing existing demand. While a high conversion rate is generally desirable, it doesn't differentiate between new and returning customers. A low ACOS (Advertising Cost of Sale) is important for profitability but doesn't specifically measure new customer acquisition. Attributed sales show the total sales generated by a keyword but don't specify the new-to-brand component, which is crucial for acquisition goals.