Personalized Marketing Can Be Ineffective—and Creepy. Here Are 3 Research-Backed Tips for Getting It Right.

Emails like these are one form of personalized matching, a persuasive tactic that dates all the way back to Aristotle, who believed speakers must consider the emotional state of their audience when making arguments. Modern technology has bolstered the effectiveness of this ancient strategy, making it possible for marketers to gain ever more detailed information about potential customers—and use that knowledge to grab and hold their attention.

At the simplest level, matching (also called segmenting, targeting, tailoring, customizing, or personalizing) takes place when “a persuasive message has a characteristic in common with the recipient of that message,” explains Jacob Teeny, an assistant professor of marketing at the Kellogg School.

But despite the ubiquity of matching, we know surprisingly little about when, why, and how it succeeds.

That’s why Teeny and colleagues—Joseph J. Siev and Richard E. Petty of the Ohio State University and Pablo Briñol of the Universidad Autónoma de Madrid—decided to review a large body of published studies on personalized matching to see what they could uncover.

“There was an outstanding question of, why do personally matched messages work?” Teeny says. “This review allowed us a chance to give more of a bird’s-eye perspective on some of the underlying mechanisms behind the phenomenon.” Also important: it would help them see when it fails.

So what did they learn—and how can marketers use this information to their advantage?

Teeny offers three tips based on the team’s research on when and how to make matching most effective.

1. You still need a compelling message about your product.

If you’re going to use matching in your marketing, it’s essential to make sure that you’ve got a strong message about your product.

Why? Matching, the research shows, can prompt increased “elaboration”—the amount of mental effort and engagement you put into contemplating a message. The more closely matched the message is, the more likely you are to contemplate it. This heightened attention, Teeny and his coauthors believe, is a primary source of personalized matching’s power.

For example, in one study, participants were asked whether they focused more on their external appearance and social image (high self-monitors) or on their internal beliefs (low self-monitors). Then, participants saw a shampoo ad that either highlighted the shampoo’s appearance benefits (a match for high self-monitors) or its effectiveness (a match for low self-monitors). The ads also varied in how strongly they made their case.

Participants paid more attention to ads that matched their level of self-monitoring: when surveyed on their opinions of the products, participants rated matched ads that contained strong arguments more favorably than either mismatched ads containing strong arguments or matched ads containing weak arguments. In other words, participants seemed to more fully process the content of matched ads than mismatched ads—making it critical that the content actually be compelling.

The study showcases the double-edged sword of matching: Marketers want consumers to pay attention. But if a highly relevant ad catches their eye, only to disappoint them with lackluster claims, matching can easily backfire.

“If you’re using matching, don’t just think you can throw it out there and all of a sudden it’s going to work. It has to be accompanied by some compelling reasons,” Teeny cautions.

That’s especially true if you’re targeting people in ways, in places, or at times when they have lots of opportunity to think. A billboard along the highway, Teeny notes, naturally allows for less elaboration than an ad at a train station, where people may be standing around for a while.

Heightened elaboration also means that matching works best when it’s employed in a way that’s actually relevant to the product. “For a political ad, using language that matches the person’s morality is going to be more successful, because politics and morality are obviously connected,” Teeny says. But trying to appeal to morality when selling, say, a pair of jeans may not work as well.

2. Look for unexpected ways to match, and choose the ones that are most important.

Factors such as age, gender, and political beliefs are the bread-and-butter of personalization—for good reason. But the research shows there are lots of other, less expected ways to target customers, like the physical or temporal context in which you are reaching them.

“One thing that surprised me was how matching qualities of the environment can influence you,” Teeny says. “If you’re a daytime person and you get an email during the day, you’re going to read it more carefully than if it came at night.”

For instance, one study found that playing highly emotional music in a store increased purchases among impulsive shoppers. Even the virtual “setting” of an online retailer can influence purchasing intentions: utilitarian shoppers prefer simple, easy-to-navigate websites, while pleasure-focused hedonic shoppers prefer a more immersive experience. Understanding which type of customer you want to reach can help you decide what type of environment to create for them.

Some ways of matching with customers rely on transitory characteristics, like a person’s emotional state; others on more innate ones, like introversion versus extraversion. To date, studies have demonstrated effective matching based on a range of factors, including people’s approach versus avoidance orientation (that is, responsiveness to incentives versus disincentives); regulatory focus (the preference for seeking pleasure versus avoiding pain); “Big 5” personality traits (levels of extraversion, openness, agreeableness, conscientiousness, and neuroticism); and even level of sports fandom.

Of course, some of these factors are more consequential than others. “Focus on characteristics that are very central to the person’s identity, rather than a peripheral trait,” Teeny advises. Appealing to, say, political orientation (assuming, of course, it’s relevant to the product or message) will probably have more lasting persuasive effects than matching based on a consumer’s favorite color.

Teeny and his coauthors also found evidence that personalizing a message along multiple dimensions simultaneously can increase persuasion. For instance, one study on smoking cessation found that highly personalized messages were more effective than minimally personalized messages that just contained the participant’s name.

3. Don’t be creepy (or unethical).

How personalized is too personalized? It’s an important question, Teeny says, one that marketers and researchers are still trying to calibrate.

While consumers are broadly aware of (and mostly resigned to) the reality that their online data is being tracked, certain types of targeted ads hit too close to home. Consumers react poorly, studies found, when they receive messages based too closely on their transaction history or if they realize the information being used to target them was collected from another source’s website.

“If you’re scrolling and think, ‘Whoa, that ad is really tailored for me’—as soon as you have that metacognitive awareness, it starts to bring in a feeling of, ‘Oh, I think they’re trying to manipulate me,’” Teeny says. In other words, when consumers become consciously aware of the targeting, the sense of feeling tricked can cause the match to backfire.

People also react poorly to being targeted on characteristics they feel are negative or rooted in stereotype. When consumers believed they had received an ad for a weight loss program based on their size, they perceived the ad and its messages more negatively.

In addition to concerns about what consumers will tolerate, marketers should also consider ethical questions around targeting—questions that are looming larger as technology improves, Teeny says.

For example, it may be possible, based on someone’s online behavior, to determine that they are suffering from depression. Is it ethical to use this information to show them ads for chocolate ice cream?

“Where do we draw the line? That’s a really interesting and difficult question and something that really doesn’t have a lot of regulation,” Teeny says. “I think this is a really important topic of discussion and something that deserves further large-scale investigation.”