Here is the summary from a recent comScore study.
Summary
Assuming that proper Web traffic hygiene such as filtering “bots” and internal traffic is conducted correctly, it’s possible to explain most differences between panel-based data and server-based data with the following simple equation:
Difference = (Inflation Due to Cookie Deletion + Inflation Due to Cookie Blocking) * Inflation due to unfiltered International Traffic
Due to the multiplicative nature of these effects, the overall inflation can reach 10x or more. For example, a site that has a 2.5x cookie deletion inflation and 4.5x inflation due to international traffic will have a staggering overall inflation of 11.25x in its counting of unique visitors.
Deleted cookies disconnect users from their actions.
Request your copy of the Cookie Deletion White Paper at comScore.
The international effect is well known among newspaper and magazine publishers. We call this the flyer paper effect. Throw enough paper into the air, something sticks.
Comment by bill — February 6, 2008 @ 5:06 am |
Always suspected that the metrics from many sites are largely bullshit. Good reporting.
Comment by Anonymous — February 6, 2008 @ 5:13 am |
“Counting of impressions has proved to be difficult due to the Internet infrastructure. This is caused mainly by caching which is intended for cutting bandwidth costs
(Lockhorn 2001) but creates discrepancies between publishers’ impression counts and third-party ad servers’ counts used by the advertisers. As a result, advertisers cannot be certain whether the counting discrepancy is due to the ad serving technology or due to the publishers’ acting opportunistically and under-delivering. The average discrepancy rate is reported to be between 20% and 30% (Picard 2002) and has been widely cited as the reason for traditional advertisers not embracing the CPM model on the Internet (Lockhorn 2001).”
Lockhorn J., July 11, 2001. Cache Busting: Busted?
Picard, E., October 28, 2002. The Three Big Ad Headaches
Comment by bob — February 11, 2008 @ 6:11 pm |
The news comes after years of frustration from advertisers and publishers with comScore and Nielsen Online’s numbers. The Internet Advertising Bureau found marked discrepencies between ComScore and Neilsen Online’s reported numbers and member websites’ own internal logs. In one case, Nielsen Online reported mlb.com drawing in 6.2 million monthly users, while mlb.com’s internal metrics showed over 19 million. Nielsen Online and ComScore have agreed to audits in 2007 by the Media Ratings Council, audits that have yet to be completed.
Comment by VentureBeat — June 24, 2008 @ 5:40 pm |