A control group is a portion of participants in an experiment that are not exposed to any test variables. They use a product or a website in its original form, without being subjected to any changes.
The control group is used as a benchmark in comparing the impact of variables used in other test groups and determining which change is the most desirable and performs the best. This allows marketers to limit their observation of the impact of variations to that of the independent variable.
The size of a control group is determined by certain factors, such as the size of the total population or users you are testing and the acceptable margin of error, among others.
Control Groups in A/B Testing
The creation of a control group is beneficial in A/B testing because a segment of the population tested serves as a basis on how two variations of any part of the user experience compare. It is often an overlooked component of the testing, but it is important to the process because it allows marketers to see if a variable is beneficial to the brand at all. A company can opt to apply one of the variations or to maintain the original conditions in the control group.
Why Is Using a Control Group Important
It is easy to fall to confirmation bias when testing. Control groups help avoid that because there is more information that would not necessarily confirm a given assumption. Sometimes there are external variables that can impact the results of testing. A control group also allows for a more accurate, nuanced analysis.
Control groups can highlight which conditions work best against a benchmark. Its creation keeps companies from overlooking opportunities for profit. As such, brands can determine which variables can bring in the most revenue. You can also measure the impact and the success of your marketing campaigns.
Conditions Where a Control Group Matter
Some conditions and customer behaviors require brands to respond quickly and adjust their marketing campaigns. Here, control groups help measure even the incremental effect of their efforts. Some of the circumstances where testing might be beneficial include having repetitive promotions. Many shoppers will not respond to campaigns they see over and over again. Testing can help reset the targets so that the efforts still impact significant segments of the population.
Visitors can also fall to customer fatigue. There can come a point when shoppers would have enough of campaigns and have reduced engagement with your attempts to convert. Control groups can help determine which efforts to remove. Brands can retain parts of the customer experience that still make an impact.