If you truly want to know the impact your digital marketing campaigns are having, then compare the actions of people who get them to the actions of people who wanted to get them but didn't. That’s the logic behind universal control groups, which is a measurement approach where you exclude a small portion of your audience from campaigns to get a baseline for measuring their impact over time.
By withholding campaigns from people who would normally receive them, brands are able to control for level of interest and intent in a way that you couldn’t if you simply compared people who got the campaign to people who weren’t eligible to get them. That’s why many consider universal control groups to be the purest way to measure the lift generated by your marketing efforts.
However, implementing a universal control group involves some complexity. So, let’s discuss the various issues so you can do one successfully.
First, measuring the results of a universal control group isn’t like determining the winner of an A/B test. That’s because your campaign recipients are reacting to the campaign and your control group isn’t. That makes it impossible to use the key performance indicators of the channel you’re using for the campaign.
For a control group to be properly analyzed and compared to the group of campaign recipients, it needs to be measured against broader KPIs that go beyond the channel you’re analyzing. For example, if you were doing an email marketing universal control group, then you’d need to track metrics like web visits, in-store visits, conversions, purchases, and revenue, while ignoring email channel metrics like email opens and clicks.
Therefore, having visibility across all sales channels at the individual customer level is a prerequisite of using a universal control group. This likely means that you’ll need to work with
the different teams at your company that manage the channels needed to get that broader view. Technologically, having a customer data platform (CDP) like Oracle Unity can be a huge advantage in terms of getting that visibility.
Selecting Control Group Members
Picking the wrong audience to be a part of your universal control group can make it meaningless before you even begin. There are five factors to consider.
First, identify the channel that you’re looking to measure, whether it’s email, loyalty, SMS, or another. In some instances, brands will narrow their audience even further so they can measure the impact of, say, their B2B lead nurturing campaigns.
Second, you want to pick an audience that’s representative of your overall audience in the channel. You don’t want to pack your control group with your most active audience members, but you also don’t want to fill it with only marginally engaged ones either. Be intentful about your selections.
Third, make your control group large enough to be statistically significant. At the same time, you don’t want it to be too large, as that makes it unnecessarily costly. The goal is to have it be as small as possible while still generating definitive results after a few months. Work with an analyst to determine the best size for your universal control group.
Fourth, you’ll want to refresh your control group periodically. After all, the people in it opted in to receive your campaigns. Withholding them forever is a poor customer experience. Plus, it eventually creates control group fatigue, where the group engages with email less in general and turns to other channels, skewing results. We recommend turning over your control group every 6 months, and reviewing results either quarterly or at the conclusion of each group.
And fifth, you’ll want to make sure that there isn’t any overlap between universal control groups that you have in different channels. For example, you don’t want the same people to be simultaneously withheld from receiving SMS campaigns and loyalty campaigns (unless your goal is to study the intersection of multiple channels).
Because you’re withholding campaigns from a portion of your audience, you’re losing out on the potential revenue from successful campaigns that would have been sent to them. That cost isn’t insignificant—and, indeed, is one of the things that keeps more brands from using universal control groups.
In addition to minimizing the size of their control group to reduce costs, some brands also:
However, recognize that all of those cost-saving measures also have the effect of diluting the impact readout. For example, seasonality is a major performance factor for many B2C brands, so shutting down your universal control group during peak seasons will significantly reduce the lift of the channel being analyzed.
You can avoid having to sacrifice the integrity of your results by gaining internal buy-in and organizational alignment in advance of setting up your universal control group. Try to get everyone to agree that a small impact to performance is worthwhile to gain the valuable insights that can come from an analysis like this.
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The Value of Insights
In exchange for the direct costs of setting up and managing a universal control group and the opportunity costs of not communicating with this group, brands gain valuable insights. Those include:
1. Channel lift
The most obvious insight is the ability to understand how much lift your digital marketing efforts are generating by comparing the activities of your control group and those not in the group.
2. The value of a subscriber
Dividing channel lift by the number of subscribers for that channel (excluding the number in the control group) tells you the value of an individual subscriber. This can help you quantify the cost of list churn, as well as put a value on list churn mitigation efforts
Knowing this number can also inform how much you’re willing to invest in acquisition efforts in terms of spending thresholds and budgets. Of course, not every acquisition source produces subscribers of equal value, so you’ll want to be mindful of that when allocating budgets to different acquisition activities and channels.
Check out our checklist of 18 Audience Acquisition Source Ideas for guidance on low-, medium-, and high-risk acquisition sources and how to optimize each one.
3. Channel return on investment
Having data from a universal control group allows you to do a much more sophisticated ROI calculation for the channel involved. For example, during a time period, you could start with channel lift and then subtract (1) the operational costs related to writing, designing, and sending campaigns and (2) the costs of acquiring new subscribers.
Oracle Digital Experience Agency routinely helps our clients set up and maintain universal control groups and calculate those three metrics. In addition to those insights, because you’re tracking the impact of channel messaging on behaviors across other channels, you gain a better understanding of cross-channel influences.
For example, one of our large retail clients used a universal control group and realized that their email marketing had a substantial impact not only on digital sales, but also in-store sales. This analysis was used to advocate for more email marketing budget and resources.
And that’s probably the ultimate goal of most universal control group efforts: to better understand channel performance and influence so that marketing resources can be allocated in the most productive way. That level of understanding is important for channel operators, and critical for marketing leaders.
Need help setting up or managing a universal control group? Oracle Digital Experience Agency has hundreds of marketing and communication experts ready to help Oracle customers create stronger connections with their customers, partners, and employees, even if they’re not using an Oracle platform as the foundation of that experience. Handling everything from creative and strategy to content planning and project management, we consistently exceed our clients’ expectations, earning a customer satisfaction rate of 96%.
Peter Briggs is a Director on the Strategic Services team at Oracle Marketing Cloud Consulting. His background includes over 12 years of client and agency consulting experience in the digital marketing space. Peter’s versatile experience and unique blend of creativity and analytical thinking enables him to develop innovative solutions that deliver results.
With over a decade of proven success in digital marketing performance on the corporate and agency levels, with a focus in email, direct, and web marketing and encompassing non-profit, association, commercial, travel, financial, retail, B2C, and B2B, Tommy Hummel bring a wealth of experience and expertise in digital marketing strategy, planning, leadership, and client service.