We’re often asked why data collected by Google Analytics and data collected through your paid media campaign are different. The answer is simple, cookies.

 How cookies affect your results

 Google Analytics consists of three basic parts:

  1. Google Analytics JavaScript code, added to your website pages.
  2. Cookies, which Google uses to collect data from visitors.
  3. A processing engine that creates reports out of the data collected from visits to your website.

When a visitor lands on your site the Google Analytics code will record the visitor's browser and computer settings, like screen resolution, operating system, region, etc. The script then sets cookies containing some basic visit information, sort of like a trail, something the code can detect in the future.

 By leaving these cookies behind, the script can then determine on the next visit if it is a new or returning visitor, length of visit, page views, bounce rates, etc. Google Analytics will then process and store this data, which we can then use to create reports.

Studies show that between 10% and 25% of users disable third-party cookies. 

 Now, one thing that affects the data collection is whether or not an individual user has their cookies enabled. It is possible to disable your cookies, which means when visiting a site your information will not be collected. That’s one reason why sometimes your results for paid media traffic are different than Google Analytics.

 So, for example, your media data from a specific campaign may say you received 1000 clicks whereas your Google Analytics report shows you’ve only had 800 visits. What that means is 200 of the 1000 people who visited your site because of your campaign had their cookies disabled and Google Analytics was unable to collect their data.

So, why use Google Analytics?

 Because it’s awesome!

 It is like watching people in your store. Google analytics tells you everything they did on their visit; how long they were on pages, where they went etc. Paid media data on the other hand focuses on how your ads performed specifically (clicks, click through rates, impressions, etc.)

 BOTTOM LINE: Google Analytics offers marketers some incredibly useful data, but should only be considered a survey sample of visitors to your site, not hard facts.