Facebook’s newly introduced capability to target advertising by Zip code may not be ready for prime time, according to research by a company that specializes in analyzing the performance of Facebook ads.

During a session at the SES San Francisco search and social marketing conference, data collected by ad testing system showed that Facebook’s estimated addressable audience per zip code was considerably different from what the census data says is the case (see below).

Rob Leathern, CEO of’s parent company, used the cities of Fremont and Pleasanton in Northern California as examples. Leathern said Facebook gives the addressable audience in the Pleasanton Zip code of 94566 at about 808,000. The U.S. Census says it’s closer to 41,000, less than 5 percent of Facebook’s figure.

“Zip code targeting based on IP has historically been less than 50 percent accurate in display advertising, and Facebook is not much different (yet),” Leathern told “Facebook does have the advantage of a lot of user-supplied location data as well, and we’re pretty confident from talking to them that they’re in the process of figuring it out and improving the targeting capabilities for advertisers.”

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Photo courtesy of the United States Census Bureau

Chart courtesy of