Viral vs Classic: A/B Testing in a World of False Positives

The term A/B test is very misleading. The term implies that there are only two things that you need to consider when running one. The control group and the experimental group. In actuality, when focused solely on these two elements, marketers are at risk of media spend waste, “false positives”, and plateauing results. There are 3 common oversights when conducting an A/B test. A misfocus on averages, test “contamination”, and failing to consider short term vs. long term effects. Each pitfall affects different industries in different ways. In the automotive industry, where each purchase is, more times than not, a large financial decision that is not decided in a short span of time by the consumer, the lack of consideration of short term and long term results is a major misstep.

The Novelty Effect

Would you rather go viral or be a classic? Sure, instant results may feel good, but standing the test of time is what truly separates standing the test of time vs. a phase. From an advertisement perspective, the same logic applies. With the novelty effect, people are naturally more prone to interact with an ad simply due to the fact that it is new to them. If your messaging, branding, and creative does not resonate deeply with your target audience, they will eventually become disengaged with that content in the long term. Considering the fact that an automotive purchase or lease will more frequently take a longer time for a consumer to commit to, marketers must take this logic into consideration.

How Long Should I A/B Test?

When considering the length of an A/B test, you need to understand how long the customer decision process takes in your industry. Do not generalize your entire audience, but break down that length by multiple segmentations. For example, according to a 2025 study by Root & Associates, when evaluating the decision process from a vehicle condition (New, CPO, and Used) the average amount of time varies from 46.9 days (Used) to 48.5 days (New). However, when segmented by age, we see a much wider variation. Baby Boomers take the least amount of time (84 days) while Gen Z buyers take the longest (147 days). The flight length of your A/B test should mirror the amount of time that it takes your target audience to make a purchase. 

An A/B test is only as valuable as the strategy behind it. If you cut corners and treat it like a quick pulse check, you may get attention in the moment, but you’ll miss what actually drives a customer to act. In the automotive world, where buying or leasing a car can take weeks or even months, the goal isn’t to chase a spike of engagement but to measure what truly resonates and withstands. By aligning your test length with the consumer’s decision timeline and avoiding these common oversights, you’re not just running an experiment, you’re building a strategy that lasts.