• by Erik Sass , Staff Writer @eriksass1, March 23, 2012

Marketers may be underestimating the impact of their social media efforts by almost half, according to Adobe’s latest Digital Index report, which evaluated how marketers measure Web site traffic from sites including Facebook, Twitter, Pinterest, Tumblr, Blogger, YouTube and Yelp, including an analysis of over 1.7 billion visits to more than 225 U.S. companies’ Web sites.

Adobe noted that social media marketing is now widespread, with 73% of marketing executives saying their companies use social media in a 2011 survey. However ROI remains a major, unresolved issue: 88% of executives in the same survey said they were dissatisfied with current forms of measurement, with 52% citing ROI difficulties as the single biggest obstacle in social media marketing.

Indeed, common social media metrics are actually shortchanging social media sites (and marketers’ social media initiatives) by a significant amount. Adobe said that the discrepancy in measurement is largely due to the reliance on “last-click” attribution, and recommended “first-click” attribution models as a more accurate approach to measuring social media’s contribution, which often engage customers earlier in the buying process.

Switching to a first-click attribution model can raise social’s contribution to the buying process by as much as 94%, Adobe added. Thus the first-click attribution model for retail Web sites suggests an average value of $1.13 per visitor from social media sites, compared to just $0.60 per visitor when using last-click attribution.

Adobe assessed the average value of visitors referred to retail sites by a number of leading social media sites using both first-click and last-click attribution models, and discovered much higher values under the first-click metrics across the board. The average value was 91% higher on Facebook, 76% higher on Pinterest, 314% higher on YouTube, and 372% higher on Twitter, to name a few examples.