Repeat purchases are the key metric for measuring loyalty goals in Amazon Ads, reflecting the ability of your campaigns to drive customer retention and brand loyalty.

• Return on ad spend (ROAS)
• Ad engagement
• Repeat purchases

The correct answer is: Repeat purchases

Explanation: To measure your loyalty goals in Amazon Ads, you track the number and rate of repeat purchases. A repeat purchase occurs when a customer returns to buy from your brand again after their initial purchase. This is the most direct metric for customer loyalty, indicating customer satisfaction and strong brand preference. Monitoring repeat purchases helps assess the effectiveness of your retention and loyalty-building strategies, telling you which campaigns are encouraging shoppers to come back for more.

Reference: https://advertising.amazon.com/objectives/customer-loyalty