Primitive (and perhaps misleading) estimates on effective ROI have driven many local publishers up the wall. During Yelp‘s IPO period, one analyst suggested that it cost pizza shops almost a hundred dollars in advertising on Yelp for every pizza sold.

To combat such mistakes and show how local ad dollars are really working, Yelp has come out with a new “Estimator,” which seeks to close the loop on the value of each lead. Any merchant that has claimed a Yelp page can track leads and engagement that Yelp brings in via phone calls made from its App , check ins, or uploaded photos.

VP of Revenue and Analytics Matt Halprin, recently recruited to Yelp from Boston Consulting Group (where he worked on similar SMB analysis, as covered by our colleague Steve Marshall), noted that SMBs are confused about the value of their Yelp advertising compared to other channels, such as circulars, coupons, display and radio.

The Estimator, which is based on actual data pulled from Yelp’s logs, will give SMBs a much better idea of Yelp’s effectiveness, he says. But it “undercounts customer leads. We can’t see calls coming from consumers who are looking at their laptop and then making phone calls. It also can’t track customer walk-ins.”

Already, the Estimator has determined that Yelp advertisers do significantly better than non-advertisers. A local business that has claimed a Yelp page sees an $8,000 annual lift from Yelp, but advertisers see a lift that is $23,000. Halprin notes that typical ad packages run about $4,000 a year, or $350 a month.