Which metric describes the cost of advertising based on the number of leads generated?

The metric that describes the cost of advertising based on the number of leads generated is Cost-per-lead (CPL). This metric is essential for evaluating the efficiency of marketing campaigns, particularly in lead generation contexts. By calculating CPL, advertisers can determine how much they are spending to acquire each lead, which helps in assessing the return on investment (ROI) for their advertising efforts.

CPL focuses specifically on the outcomes of interest to marketers, namely obtaining usable leads that can potentially convert into customers. This makes it a critical metric for brands and businesses that prioritize lead generation in their advertising strategies.

In contrast, other metrics like effective cost-per-mille (eCPM) and real cost-per-mille (rCPM) concentrate on impressions and ad visibility rather than the specific outcome of generating leads. Volume is a broader term that encompasses various forms of measurement and does not specifically convey the cost related to leads. Thus, CPL is the most relevant metric for understanding the cost associated with lead generation.