Local websites could be overstating their unique browsers by as much as 170%, according to a study by comScore.
The study, which independently examined sites, found that each month 28% of Australian users delete cookies - small text files stored on a user's computer by a website. It also found that each month 37% of Australian internet users delete cookies deposited by advertising.
Cookies are often used to count unique browsers, which are used by sites to sell their audiences to advertisers. If a cookie is deleted, the website stores another cookie on the user's computer, which could lead to an overvaluation of unique browsers, comScore said.
The study found that website servers which use cookies to count unique browsers can overstate their figures by as much as 2.7 times or 170%.
Meanwhile, advertising servers using cookies to measure a campaign's reach and frequency can overstate reach by 5.7 and understate frequency by the same degree.
ComScore is one of the measurement organisations competing in a five-way pitch to become the sole online audience measurement provider in Australia. The pitch is being overseen by the Interactive Advertising Bureau (IAB) of Australia.
Have something to say on this? Share your views in the comments section below. Or if you have a news story or tip-off, drop us a line at adnews@yaffa.com.au
Sign up to the AdNews newsletter, like us on Facebook or follow us on Twitter for breaking stories and campaigns throughout the day.