Online ad metrics

ClickZ Columnist Heidi Cohen reminds us about the basic metrics for measuring the success of an online ad campaign in "A Metrics Checklist."

Here's a refresher on metrics definitions:

Click-through rate (CTR) = clicks/impressions

Total advertising cost = [(impressions/1,000) x CPM] + creative costs + relevant marketing costs

Cost per click (CPC) = total advertising cost/click-throughs

Conversion Rate = registrations/click-throughs

Cost per acquisition (CPA) = total advertising cost/acquisitions

Cohen cautions that too many advertisers measure success by click-through rates and not cost per acquisition. A big CTR doesn't tell you anything about ROI.