Digital measurement firm comScore has publicly released its white paper addressing how cookie deletion affects server-based audience measurement. The study estimates that without appropriate
adjustments, site-server audience reports can be inflated up to 2.5 times the actual number of unique visitors.
Variations between panel-based and server-based audience measurement is
one issue that prompted the Interactive Advertising Bureau to call for audits of comScore and Nielsen//NetRatings.
Download the complete comScore analysis here.