If you were under the impression that Facebook ads don't work, comScore begs to differ - and has just the numbers to prove it. The research firm teased a new report set to be released this week, presenting "new findings about the effectiveness of paid and earned media exposure on Facebook."

"Through our research, which examines the impact on consumer behavior as a result of media exposure (i.e. seeing a brand message), we are gaining critical new insights that show Facebook earned media is having a statistically significant positive lift on people's purchasing of a brand," wrote comScore in a company blog post.

The research firm will release its findings, along with a new white paper called "The Power of Like 2: How Social Marketing Works", at the ART Audience Measurement 7.0 conference, set to take place next week in New York. ComScore's new report comes in a wave of uncertainty and doubt regarding the social networking company's advertising business. General Motors pulled its ads from Facebook in May, causing a lot of uproar, saying that its ad campaigns on the site were having little impact on consumers.

ComScore Report vs. Reuters Survey

Reuters recently published a survey which found that 80 percent of Facebook users reported to "have never bought a product or service as a result of advertising or comments on the social networking site." Referring to the Reuters survey, comScore warned against reading too much into it.

"While surveys can be useful in assessing ad effectiveness lifts across attitudinal dimensions such as brand awareness, favorability, and purchase intent, people tend not to provide very accurate assessments of their own behavior," wrote comScore.

"[P]eople generally don't like to believe that advertising actually has an effect on their behavior, even though time and time again various forms of advertising research have shown that it does. So, how people respond to a question asking whether or not Facebook advertising (or any other advertising for that matter) has affected their purchase behavior may end up having little correlation with their actual behavior," added the research firm.

Perception of Ad Effectiveness

ComScore also noted that although perceptions can be influenced by the notion that an online ad can be considered effective only if it generates "click-throughs," consumer "view-throughs" of online advertising have proven effectiveness nonetheless. The research firm added that now there are new methodologies for determining the effectiveness of online ads, "due to the realization that clicks are a weak indicator of true campaign performance because they ignore the importance of simply viewing an advertising message (otherwise known as the 'view-through' impact of exposure)."

According to comScore, user exposures to an online ad or brand on Facebook should not necessarily be expected to have immediate results. Changes in consumer behavior following a successful marketing campaign can be latent, taking "weeks or even months following exposure" to an ad, explained the research firm.