Abraham

comScore has issued an open letter in response to a recent Ad Week article citing publishers who question the accuracy of comScore and Nielsen/NetRatings metrics.

comScore President and CEO Magid Abraham published an open letter addressing web analytics challenges and publishers' claims that panel-based audience metrics are faulty because they do not match publishers' web server logs, iMedia Connection reports. "When you scrutinize the details, the answer on why these two measurements don't always match up is… 'it depends.' Depends on what? The exact definition of what is being compared," Abraham writes in his long and detailed open letter.

"In fact, the reasons for discrepancies depend on a number of factors: the panel data could be wrong, the web log data could be wrong - or more often - they are both right given the exact definition of what they measure. But, those definitions could be vastly different," Abraham is quoted as saying.

comScore also stated that "transparency must go both ways," with publishers disclosing what metrics they are using and how they are calculated.