How Brands Grow

Why do some brands seem to grow effortlessly while others stagnate despite flashy campaigns and bold differentiation strategies? In How Brands Grow, Professor Byron Sharp turns decades of marketing theory upside down by asking—and answering—this fundamental question: what really drives brand growth? He argues that many marketers chase illusions of loyalty, differentiation, and niche targeting, while ignoring the scientific laws that describe how consumers actually behave.

Sharp’s contention is simple but counterintuitive: brands grow not by deepening loyalty among existing customers but by reaching more people—especially light and infrequent buyers. Every thriving brand wins by increasing its popularity, not by cultivating small pockets of devotion. Marketing, as Sharp relentlessly shows, is less about persuasion or emotion and more about mental and physical availability—making your brand easy to think of and easy to buy.

A Scientific Approach to Marketing

Sharp’s approach stems from decades of research conducted by the Ehrenberg-Bass Institute for Marketing Science. Instead of anecdotal case studies, he presents empirical laws—statistical patterns in consumer behavior that hold true across products, countries, and decades. Among these are the Double Jeopardy Law, which shows that small brands suffer both from fewer buyers and slightly lower loyalty; and the Law of Buyer Moderation, which explains that consumers’ purchasing levels naturally fluctuate over time rather than reflecting deliberate shifts in loyalty.

These findings demolish myths that have dominated marketing textbooks since Philip Kotler’s era—such as the idea that segmentation and differentiation are the keystones of growth. Sharp demonstrates that differences between rival brands’ customers are tiny. The buyers of Pepsi look remarkably similar to those of Coke, Ford’s car owners mirror Chevrolet’s, and loyalty programs, despite their promises, barely move the needle on repeat purchase behaviors.

Mental and Physical Availability: The Real Drivers

At the heart of Sharp’s thesis lies the dual concept of mental and physical availability. Physical availability means being easy to find and purchase—through widespread distribution, convenient formats, and accessible pricing. Mental availability refers to the likelihood that your brand comes to mind in buying situations—the network of memory cues built through consistent, distinctive branding and wide-reaching advertising. Brands with strong mental and physical availability get chosen simply because they are the easiest options for busy, distracted consumers.

Sharp emphasizes that buyers aren’t passionate fanatics, as emotional branding gurus claim. They are “uncaring cognitive misers” who make quick, habitual decisions based on what’s familiar and visible. Advertising doesn’t persuade with clever arguments—it subtly refreshes memory structures and nudges purchase probabilities, often without consumers even realizing it.

A New View of Advertising, Loyalty, and Differentiation

To make these scientific laws actionable, Sharp reframes many marketing practices. Advertising’s main purpose is to maintain salience—to remind people your brand exists and fits their needs—rather than to win short-term conversions. Price promotions, loyalty programs, and emotional campaigns all have limited long-term effects because they fail to build memory and distribution advantages. Distinctiveness, not differentiation, becomes the goal: brands should stand out visually and verbally to trigger recognition, not pretend to offer unique emotional meanings.

This philosophy echoes Parkinson’s Law of triviality: marketers often obsess over imaginatively “different” positioning or brand personality while neglecting the basics that make their brand visible and easy to buy. The challenge, Sharp reminds us, is not to manipulate consumers’ hearts but to earn their attention consistently across time and space.

The Practical Implications

If you manage a brand today, Sharp’s evidence-based marketing requires a shift in mindset. Stop chasing loyalists, fascination, and differentiation. Instead, focus on building reach, availability, and distinctive branding. Make sure your ad campaigns keep the brand recognizable, your distribution eliminates barriers to purchase, and your product variations exist to expand access—never to segment markets. In Sharp’s world, successful marketing means doing fewer clever tricks and more boring science. By mastering the universal laws of buyer behavior, you can spend smarter, aim wider, and build brands that grow predictably and sustainably—rather than by chance.

One of Byron Sharp’s most revolutionary insights is the Double Jeopardy Law: the empirical discovery that small brands face two simultaneous disadvantages. They have fewer buyers and those buyers are slightly less loyal. This law contradicts traditional marketing wisdom that assumes small brands survive through strong loyalty among niche audiences.

What Double Jeopardy Reveals

Sharp shows that across thousands of categories—from toothpaste to cars and beer—large brands always have far more buyers. But, strikingly, their customers also buy the brand slightly more often. For instance, Persil detergent’s buyers purchase around four times a year compared to three and a half times for smaller rival Surf. So large brands win twice—through more buyers and marginally higher purchase frequencies.

This pattern is universal. Cola drinkers in the UK buy Coca-Cola far more often than Pepsi because Coke already has more customers. Loyalty doesn’t dramatically differ; it’s just that penetration, not devotion, drives market share.

Destroying the Myth of the Niche

Marketers often imagine niche brands as small but passionately adored. The Double Jeopardy law proves otherwise. Niche products don’t have extraordinarily loyal customers—they simply have fewer of them. Any small group of heavy buyers accounts for only a fraction of sales. So “being niche” usually means suffering from limited reach or distribution, not enjoying elite customer devotion.

Sharp uses examples such as regional banks in Australia or local car brands in France to show that smaller players lose customers more frequently simply because their offerings are less available. Their attrition isn’t a matter of bad satisfaction—it’s a statistical consequence of having fewer places to buy.

Growth Through Penetration

Understanding Double Jeopardy leads to a critical conclusion: brands can grow almost exclusively by gaining more buyers, not by increasing loyalty. A brand’s future rests on expanding its penetration. When brands grow, their buyer base expands broadly among all types of customers—heavy and light alike—while loyalty metrics shift only slightly. This law gives marketers a clear guide: measure success through reach, not retention.

In Sharp’s words, breaking the Double Jeopardy law is almost impossible. Instead of striving to “beat” it, you should work with it. The creative energy of marketing should flow into achieving visibility, availability, and penetration. Or as Sharp puts it, the smart strategy is to swim downstream with the laws of buyer behavior, not against them.

Sharp dismantles one of marketing’s most seductive beliefs: that loyalty drives growth. His data reveal that most buyers of any brand are light, infrequent purchasers. Even for dominant brands like Coca-Cola, half of consumers buy only once or twice a year, yet together they contribute massive volume.

The Pareto Principle, Revisited

Marketers love quoting the Pareto rule—“20% of customers deliver 80% of sales.” Sharp revises this myth. Across categories, the heaviest 20% of buyers typically deliver only 50–60%, not 80%. The rest comes from the far larger pool of occasional buyers who are rarely targeted. In UK body-spray and deodorant markets, for instance, the top 20% of users accounted for about half of sales.

The Law of Buyer Moderation

Another key principle, the Law of Buyer Moderation, explains that purchase levels naturally fluctuate. Heavy buyers tend to buy less next year, while some non-buyers and light buyers start buying more. These shifts aren’t behavioral changes—they’re statistical regression toward an average. In one U.S. tomato sauce study, the so-called “non-buyers” contributed 14% of sales the following year, while heavy buyers contributed less than before. In other words, people move fluidly between buying levels.

Marketing That Reaches Everyone

This evidence teaches marketers a simple rule: focus on broad reach. Since growth comes from recruiting many light and occasional buyers, campaigns, advertising, and distribution must span the entire category. Loyalty programs and narrow targeting win few new buyers and barely move total sales. Meanwhile, wide-reaching advertising and accessible products naturally sustain both heavy and light buyers.

Sharp concludes that brand loyalty is widespread but shallow. Consumers buy multiple brands in rotation, not out of love but convenience and habit. The challenge for marketers isn’t deepening passion; it’s keeping their brand visible so the light buyers don’t forget to buy again.

In Chapter 6, Byron Sharp answers the deceptively simple question: who are your true competitors? Textbook marketing suggests brands compete only within narrow segments of differentiated buyers. Sharp’s data show the opposite: brands within a category share customers extensively. People buy Coke and Pepsi, Ben & Jerry’s and Häagen-Dazs, Toyota and Honda—all within their personal repertoires.

The Duplication of Purchase Law

Sharp reveals the Duplication of Purchase Law: all brands share their buyers with other brands roughly in proportion to the other brands’ size. In ice cream data from Kantar, all brands shared about 40% of their customers with category leader Carte D’Or. Ben & Jerry’s and Häagen-Dazs showed slightly higher overlap, suggesting a “premium partition,” but even their fans still bought more Carte D’Or than each other.

This law holds across categories. Pepsi buyers share about 70% with Coke; smaller brands like Lift or Fanta share roughly the same proportion. Such patterns reveal that brands don’t sell to distinct segments—they sell to overlapping repertoires.

Why Segmentation Misleads

Sharp critiques the narrow categories managers often adopt. Defining markets by product features (“chocolate-coated candy” vs. “wrapped chocolate”) blinds marketers to how consumers actually buy. Real buyers ignore these partitions; they buy based on convenience or variety, not textbook segmentation. When researchers analyzed breakfast cereals, they discovered shoppers put hot milk on cold cereal—defying artificial category distinctions entirely.

Strategic Takeaways

For managers, the duplication analysis offers practical uses: it clarifies competitor sets, predicts cannibalization between sister brands, and exposes unrealistic segmentation assumptions. Sharp’s advice—think like a “sophisticated mass marketer” who competes broadly and builds reach across the full market. Instead of worrying about micro-segments, focus on being easy to find and buy within the mass market itself.

Marketers love the idea of customers who “love” their brand—fans who tattoo Harley-Davidson logos or defend Apple online. Byron Sharp dismantles this romantic myth with data. Even supposedly cult brands have ordinary, light, and divided loyalties. In his research, most Apple owners replace their computers with other brands about as often as Dell or HP buyers do.

What Loyalty Really Means

Loyalty exists, Sharp says, but it’s practical, not emotional. Buyers adopt habitual behavior because it saves effort. Like Tucker’s bread experiment, consumers keep returning to a brand even when differences are trivial. It’s a time-saving choice rather than a heartfelt commitment. Surveys show that fully loyal customers—those buying only one brand all year—typically represent just 10–15% of a brand’s buyers.

Polygamous Loyalty

Most consumers are “polygamously loyal.” They buy a small repertoire of brands repeatedly, switching unconsciously. Loyalty isn’t exclusivity—it’s probability. Someone might buy BMW 60% of the time and Audi 40%. Their decisions look random, driven by opportunity and mental availability rather than emotional bonding.

Lovemarks Debunked

Sharp criticizes Kevin Roberts’ concept of “Lovemarks,” which claims successful brands transcend rationality through emotional love. Data doesn’t support this. For Australian beer, only 4% of drinkers said they “loved” their favorite brand—and these supposed lovers still bought it only half the time. Even Harley-Davidson zealots represent under 10% of owners and contribute a mere 3.5% of sales.

Sharp’s lesson: treat loyal customers kindly, but don’t mistake enthusiasm for growth potential. Brands depend on vast numbers of indifferent buyers who represent most of sales. Marketing success lies not in creating love but in removing barriers to ongoing, habitual repurchase.

For decades, marketers have been told to “differentiate or die.” Sharp and Jenni Romaniuk flip this motto: “Stop differentiating—start being distinctive.” They argue that differentiation, the idea that brands must offer unique meaningful differences, is overrated and often imaginary. In real life, competing brands are functionally similar, and buyers rarely perceive special distinctions.

The Evidence Against Differentiation

Survey data show that rival brands earn almost identical image scores. Larger brands simply score slightly higher because more people use them. When usage is controlled, perceptions flatten: Coca-Cola, Pepsi, and Fanta are all seen as fun, refreshing, and familiar. Even Apple’s perceived uniqueness turns out minimal—only a quarter of its users call it “different or unique.”

Distinctiveness Explained

Distinctiveness is practical, not psychological. It’s about creating instantly recognizable cues—colors, shapes, slogans, and sounds—that help consumers identify your brand. Think McDonald’s golden arches, Nike’s swoosh, or Mastercard’s “Priceless” theme. Being distinctive helps refresh memory and build mental availability. It makes it easier for consumers to spot and buy you amid cluttered shelves.

Building Distinctive Assets

Romaniuk and Sharp outline two criteria for measuring distinctive assets: fame (how many people recognize the cue) and uniqueness (how many link it only to your brand). These must be tested empirically—most companies overestimate them. Nike’s swoosh became iconic through decades of consistent use, first paired with its name before standing alone. Consistency over time—not creative reinvention—is what creates lasting distinctiveness.

Distinctiveness builds loyalty indirectly by making your brand easier to recall and notice. Differentiation fades quickly; distinctiveness lasts. That’s why Sharp calls branding less “meaning-making” and more “memory maintenance.”

Byron Sharp’s analysis of advertising overturns decades of persuasion theories. Advertising doesn’t work by convincing or inspiring—it works by refreshing memories and sustaining mental availability. The famous example of Georgiana and June’s lemonade shows this neatly: the sister who advertised steadily grew, while the one who didn’t stagnated, even though their products were identical.

Advertising’s Subtle Power

Sharp explains that advertising affects buying probabilities, not immediate sales spikes. Most ads aim to maintain market share by preventing gradual decline. Like airplane engines, advertising keeps the brand flying; when spending stops, the brand slowly descends. Because these effects are spread over time, they rarely show up in weekly sales charts.

Mental Availability, Not Persuasion

Advertising’s job is to refresh and build memory structures so the brand comes to mind in buying situations. Consumers are busy and inattentive—less than 20% of TV ads are both noticed and correctly branded. Thus, the creative challenge is not to argue but to be noticed and remembered. Emotional, likable ads often perform best because they slip past people’s cognitive filters.

In single-source studies, ads that reached large audiences quietly nudged buying propensities, especially among infrequent buyers. Each exposure doubled these consumers’ probability of choosing the brand later, even without conscious persuasion.

Contrast With Price Promotions

Unlike advertising, price promotions trigger immediate but short-lived spikes. Discounts mostly reward loyal buyers, draining profits while failing to recruit new ones. Advertising’s reach is broad and durable; promotions’ reach is narrow and fleeting.

In summary, advertising works through reach and consistency. It’s not magic or manipulation—it’s repetition. Effective ads make your brand easy to notice and recall across time, ensuring that tomorrow’s distracted shopper recognizes you as the obvious choice.

Sharp’s colleagues John Dawes and John Scriven analyze one of marketing’s favorite tools—temporary price discounts—and conclude that price promotions rarely build brands. They spike sales briefly but leave no lasting effects. When the discount ends, sales return to normal because promotions don’t change buying propensities or recruit new customers.

Why Discounts Don’t Drive Growth

Most promotions attract existing buyers who buy a bit earlier or stockpile. In grocery data, half of sales during promotions came from customers who had already purchased the brand before. These aren’t new buyers—they’re accelerated purchases. When time passes, these buyers resume their usual habits, producing an illusion of success followed by a sales trough.

Elasticities and Profit Erosion

Dawes and Scriven quantify this effect: average price elasticity around -2.5 means a 10% price cut yields only a 25% sales increase. Deep promotions often erase margins—cutting price by 45% may quadruple volume but brings little or no extra profit. Worse, frequent promotions teach consumers to wait for discounts, undermining reference prices.

Reach and Efficiency

Promotions reach only shoppers who happen to buy that week—usually the brand’s heaviest buyers. Advertising, by contrast, reaches millions cheaply and refreshes memory for future purchases. Sharp calls discounting an addiction: retailers demand it, managers love its visible spike, but it drains long-term profitability.

The takeaway? Use promotions sparingly for retail relationships, not growth. To build brands, invest in mental availability—not markdowns.

The climax of Sharp’s framework arrives with his theory of mental and physical availability. These twin pillars explain nearly every brand’s success. Growth happens when your brand is easy to think of and easy to buy. Once mastered, these assets deliver lasting profits because they decay slowly and amplify all other marketing efforts.

Mental Availability: Salience Over Persuasion

Mental availability is the likelihood that a brand comes to mind when consumers face purchase cues. It consists of memory nodes linked to situations, needs, and emotions. Coca-Cola is associated with summer, parties, pizza, and refreshment; Nike with movement and victory. Advertising’s role is to build and refresh these associations consistently using distinctive assets.

Physical Availability: Ease of Access

Physical availability means being widely stocked, easy to find, and simple to purchase. It’s not just shelf presence but also accessible pricing, formats, distribution channels, and usage occasions. Sharp cites Coca-Cola’s ambition to be “within arm’s length of desire”—a perfect metaphor for his theory.

Managing These Assets

Mental and physical availability are market-based assets: they require time and consistency to build but deliver stable returns. Brand managers should measure and manage them like financial capital. Consistent advertising, distinctive imagery, and expanding distribution all multiply their strength.

When McDonald’s lost its dominance, it recovered by refreshing its mental associations (adding coffee and healthier options) and enhancing physical availability (McCafe, longer hours). Likewise, Seppelt’s revival of “Queen Adelaide” wines succeeded by leveraging old mental connections with modern availability—all science, no magic.

Seven Simple Rules

• Continuously reach all category buyers.
• Ensure the brand is easy to buy.
• Get noticed—often.
• Refresh and build brand-linked memories.
• Create distinctive communication assets.
• Be consistent, yet fresh.
• Stay competitive; remove reasons not to buy.

Sharp ends with optimism: evidence-based marketing liberates creativity from guesswork. By mastering mental and physical availability, marketers can finally predict—and sustain—growth scientifically.