Which metric helps advertisers understand their earnings based on impressions received?

The correct metric for understanding earnings based on impressions received is Revenue per 1000 Impressions. This metric provides a standard measure that allows advertisers to evaluate how much money they earn for every 1000 ad impressions served. It's particularly useful because it normalizes earnings across different campaigns by accounting for the volume of impressions, which can vary widely.

By using this metric, advertisers can compare the effectiveness of different ad placements and strategies, as it reflects the revenue generation relative to how many times the ad is viewed. This relationship is crucial in digital advertising, where impressions are a key aspect of performance and outcomes.

In contrast, Revenue per Click focuses on the earnings gained from users who actually click the ad, while Cost per Impression refers to the amount spent to acquire impressions rather than what is earned from them. Response Rate measures the percentage of users who take a specific action after seeing the ad but does not provide insight into the earnings generated from those impressions specifically. Thus, Revenue per 1000 Impressions is the most relevant metric for advertisers studying their earnings in relation to ad impressions.