comScore released a white paper, The Impact of Cookie Deletion on Site-Server and Ad-Server Metrics in Australia: An Empirical comScore Study.
The study addresses the key sources of discrepancy between server-based and panel-based data and reveals that cookie deletion can lead to large overstatements in servers' measurement of the size of online audiences. Without appropriate adjustments, site-server measurement of the size of website audiences in Australia can be inflated by up to 2.7 times the actual number of unique visitors.
Here're the key findings:
- Appx.28% Internet users in Australia delete their 1st-party cookies in a month. 3rd-party cookie %tages are even higher, with nearly 37% deleting 3rd-party cookies in a month.
- "Serial cookie deleters" have a profound impact on inflating site-server logs because they represent a small %tage of computers, but a very large share of observed cookies.
- Comparing cookie deletion in Australia with other markets across the globe including the U.S., U.K., Brazil, France, Germany and New Zealand found that each country saw 3rd-party cookies being deleted by appx. 30-40% users, with 1st-party cookies deletion in excess of 20% in each country. Australia fell in the middle of the distribution among the included markets for both 1st-party and 3rd-party cookie deletion percentages.
[tags]cookie,web server,australia,site server,ad server[/tags]