When creating a lookalike audience, which source audience is generally most effective for maximizing conversion rates, assuming all other factors are equal?

A source audience comprised of existing customers who have made purchases, especially those with a higher lifetime value, generally yields the highest conversion rates when creating a lookalike audience. A lookalike audience is a group of people on Facebook who share similar characteristics with your existing customers. Because purchasers have already demonstrated a willingness to spend money with your brand, Facebook can identify the traits and behaviors that are most predictive of conversion. When this data is used to create a lookalike audience, the resulting audience is more likely to also convert at a higher rate compared to lookalikes based on website visitors, email subscribers, or page engagers. For example, a lookalike of the top 10% of customers by purchase value is more likely to outperform a lookalike of all website visitors.