Analytics programs are never going to be 100% accurate but you might not expect them to be over-reading by 2-4 times on your unique visitor numbers.
According to research this is exactly what’s going on. Scout Analytics has developed algorithms for tracking users across different devices using dozens of unique attributes and utilize patent-pending algorithms to derive a unique signature for the device, network, even the individual user (biometric). Their systems use things like typing patterns to identify people across different computers for example, you can read more on the blog.
During the past 6 months, Scout Analytics tracked hundreds of thousands of subscribers through a combination of patent-pending tracking technologies of device and biometric signatures. Scout Analytics discovered cookies have an inherent weakness that causes them to overstate the user counts on an average of two to four times.
â€œVirtually all measurement techniques have some rate of error, but online marketers who have a heavy reliance on cookies need to know this method has astonishingly low accuracy,â€ said John Lovett, senior partner for Web Analytics Demystified. â€œBecause of this, we expect new innovations in measurement technology in the near future that will no doubt minimize marketersâ€™ reliance on cookies and dramatically improve measurement accuracy.â€
I expect that some of the major analytics provided will be interested and worried about this. On the one hand they want their figures to be more accurate but on the other hand if they were to start using this technology all their customers unique visitor numbers would fall dramatically overnight.