Marketers who formally measure online branding may realize up to a 35 percent higher return on investment from their Internet advertising campaigns than they originally estimated, Jupiter Media Metrix said Tuesday.

But only 15 percent of marketers quantify online branding, the Internet researcher said. The majority of marketers still favor direct response metrics, including cost per click and conversion rates, Jupiter found in its survey of advertising executives.

"The actual number of customers driven to Web sites by online advertising is greatly underestimated by traditional click-rate metrics," said Jupiter Media Metrix analyst Rudy Grahn. Brand advertising programs can generate more customers than can be tracked when combined across all marketing channels, he said.

Marketers should measure the user's actual experience instead of gauging only their attitudes, he said.

Ad spending may not correlate with an increase in traffic, however, Grahn said. Online advertising contributes only 17 percent of the traffic to a Web site, while seasonality generates 46 percent and an increase in Internet adoption accounts for 37 percent of traffic growth, the report found.

Marketers can measure branding value by correlating behavioral data, including individual user click streams, repeated surfing patterns and aggregate user behavior, with the flights of specific ads, Grahn said. Advertisers have begun experimenting with calculating the relationship between aggregate spending and the corresponding volume of user behaviors, such as store locator pages hits, information requests and hits on phone-ordering information pages, the study found.

The fractured reach of online media is a major reason the Internet has resisted traditional branding practices. For example, Yahoo! has a unique user base of over 20 million in the 8 p.m. hour, which represents close to a 35 percent share of total Internet unique users for that time, according to Media Metrix audience measurement data. However, this aggregated Yahoo! audience represents traffic spread across 438 separate domains, making it difficult to generate message association online using offline marketing practices, the researcher said.