How Cookies can Skew Google Analytics Visitor Data for your site

When you are running an ecommerce site, Google Analytics is extremely useful in providing an array of visitor data. However anyone who has used Analytics to a reasonable degree will be well aware that there are factors which can affect the accuracy of the data you receive. One such factor relates to cookies. Cookies first and third party cookies are important in gathering data about your users. However there are a few ways in which cookies can fail to gather accurate data.



Visitors can reject and delete cookies


First and foremost, users can reject and delete cookies. Sometimes this is done if they do not trust a site or have certain security features installed on their computers which perform this automatically. While this mostly applies to third party cookies as users don't want their information to be passed on, a small amount also block or delete first party cookies. This inhibits the vendor's ability to measure source and pageview data.



Users own and share multiple computers


The information gathered via the cookies is often based on IP addresses. Unfortunately this information is made inaccurate by the way people interact with the site. Obviously a home computer can be accessed by several users, but from the same IP they are all registered as one. In addition a single user may use his office and home PC to view the site and be counted as two users.



Latency leaves room for inaccuracies


A lot can happen in between a user first visiting the site and actually making their purchase. For more expensive orders such as holiday booking for example a user could take months. In this time they could potentially buy a new computer, install a new operating system or make a variety of other changes. These would mean that when they make their purchase they are not registered as a returning user, but as a new user.



There are also a variety of other ways in which visitor data can be affected by flaws in using cookies. This can make it extremely difficult for SEO companies to judge how accurate visitor data is on a sight. In turn it makes it difficult to adjust the website design to improve the success of the site.



Website optimisation is a tricky procedure and although Analytics is a useful tool, the user must be able to understand how its data is affected before being able to understand it fully.