Differences in data collected from Nelio A/B Testing and Google Analytics

Nelio A/B Testing and Google Analytics have different tracking methods, which means you may find differences in the number of visitors tracked from these tools. The following are some of the most commonly reported issues and their reasons:

“Pageviews” data in Google Analytics with “(Tested) Page Views” in Nelio A/B Testing give different results

Pageviews data in Google Analytics is the total number of visits on the website. Google Analytics tracks all visits to a page (both first-time visitors as well as returning users).

(Tested) page views in Nelio A/B Testing also implements this approach: it counts both first-time and returning visitors. However, not all visitors accessing a certain page are counted by Nelio A/B Testing. Only those visitors that participate in the test will be included in the results. Visitors may be excluded from an experiment if you limited the percentage of users that may participate in your tests.

Google Analytics kicks in before Nelio does

Nelio A/B Testing includes a tracking JavaScript in all your pages. The tracking script is responsible of checking whether the current page is under test and, if it is, of loading the appropriate variant (that is, redirecting the visitor to a page that includes a GET parameter specifying the alternative to be loaded).

In principle, this process is executed before Google Analytics kicks in. But under some circumstances, Google Analytics’ code may begin to execute on the original page itself before the redirection to the variant. This could trigger an additional page view on the original page.

This unwanted behavior occurs when using plugins that combine or merge scripts without taking into account the original execution order. The same may occur when using plugins that add the async attribute to JavaScript tags breaking the logical order of execution of scripts.

Nelio A/B Testing should work properly in most scenarios. If you find problems like the ones explained here, do not hesitate to contact us. We’ll provide assistance to fix any issue you may encounter here.