Which metric is primarily used to assess the effectiveness of an advertising campaign?

Return on investment (ROI) is the metric primarily used to assess the effectiveness of an advertising campaign because it measures the financial return generated from the campaign relative to the amount spent. A high ROI indicates that the advertising efforts are yielding a profit and contributing positively to the overall business objectives.

In the context of advertising, ROI provides insights into not just whether the ads were successful in generating interest or clicks, but whether those actions translated into measurable financial outcomes — such as sales, lead acquisition, or other key performance indicators that directly impact the bottom line. Evaluating ROI allows businesses to make informed decisions about future advertising strategies, resource allocation, and budget adjustments.

Other metrics like cost-per-click (CPC), impressions served, and click-through rate (CTR) offer insights into specific aspects of campaign performance. For instance, CPC measures direct costs associated with clicks, impressions indicate how often ads were displayed, and CTR reflects user engagement in terms of clicks received relative to impressions. While these metrics are valuable for optimizing performance and understanding audience behavior, they do not directly quantify the financial return from the campaign in the same way that ROI does.