Core Marketing Laws

A distilled, evidence-based reference manual of the empirical laws governing how brands grow, how advertising works, and how people actually make buying decisions.

Law 01 Brand Growth

The Law of Double Jeopardy

Source: William McPhee (1963) / Ehrenberg-Bass Institute (Byron Sharp)
The Empirical Rule

Brands with smaller market share suffer twice: they have far fewer buyers, and those buyers purchase slightly less often and are slightly less loyal.

What Most Marketers Get Wrong

Trying to grow a brand primarily by increasing loyalty or repeat purchase frequency amongst existing customers.

Why It Works (The Evidence)

Analysing decades of panel data across dozens of consumer categories and countries, Ehrenberg-Bass demonstrated that loyalty varies very little between competing brands of similar size, whereas penetration (total number of buyers) varies massively.

How to Apply It on Monday
  • Prioritise customer acquisition and broad reach over narrow loyalty schemes.
  • Focus media budgets on reaching light and non-buyers of your brand within the category.
  • Measure market penetration as your primary brand health KPI.
Law 02 Brand Growth

Mental and Physical Availability

Source: Prof. Byron Sharp & Prof. Jenni Romaniuk (Ehrenberg-Bass Institute)
The Empirical Rule

Brands grow by becoming easier to think of in buying situations (Mental Availability) and easier to find and buy across channels (Physical Availability).

What Most Marketers Get Wrong

Assuming consumers walk around with deep, rational brand preferences rather than defaulting to the most salient, convenient option.

Why It Works (The Evidence)

Human memory is associative and decays rapidly. Brands that build links to a wide network of Category Entry Points (the cues, occasions, and problems that trigger a purchase) capture a disproportionate share of sales.

How to Apply It on Monday
  • Map out the 6 to 10 core Category Entry Points (When, Where, Why, With Whom) that trigger buyers to enter your category.
  • Create advertising that refreshes memory links between those entry points and your brand.
  • Remove friction at checkout, shelf placement, and search so physical availability matches your mental reach.
Law 03 Brand Growth

Distinctive Assets Over Differentiation

Source: Prof. Jenni Romaniuk (Building Distinctive Brand Assets)
The Empirical Rule

Buyers rarely perceive competing brands as meaningfully different, so distinctive sensory triggers (colours, logos, characters, sonic cues, shapes) are what actually make advertising work.

What Most Marketers Get Wrong

Obsessing over a Unique Selling Proposition (USP) whilst constantly changing visual identity, fonts, and campaign styles every 12 months.

Why It Works (The Evidence)

In blind attention tests, the vast majority of advertising fails to be attributed to the correct brand. Distinctive assets Measured by Fame (how many people link the asset to your brand) and Uniqueness (how few competitors trigger it) prevent your media spend from working for the market leader.

How to Apply It on Monday
  • Audit your brand assets using a Fame vs. Uniqueness grid before changing any creative element.
  • Codify 3 to 4 non-negotiable distinctive assets (colour palette, character, sonic mnemonic, pack shape) and deploy them across every touchpoint.
  • Resist internal boredom: marketers tire of campaign assets years before the public even notices them.
Law 04 Effectiveness

The Long and the Short of It (60:40 Principle)

Source: Les Binet & Peter Field (IPA Effectiveness Databank)
The Empirical Rule

Short-term sales activation generates immediate spikes that decay quickly, whilst long-term brand building creates compounding base sales and reduces price sensitivity.

What Most Marketers Get Wrong

Shifting 90%+ of budget into short-term performance marketing because last-click dashboards make it look more efficient.

Why It Works (The Evidence)

Across 30+ years of IPA Effectiveness Awards case studies, brands that split investment roughly 60% into broad emotional brand building and 40% into targeted sales activation achieved the strongest commercial profit growth.

How to Apply It on Monday
  • Ring-fence long-term brand investment so it cannot be raided for quarterly performance targets.
  • Use broad-reach, emotionally resonant creative for brand building and rational, targeted messaging for activation.
  • Judge brand campaigns over 12 to 36 months (base sales, price elasticity, share of search) rather than 7-day click-through rates.
Law 05 Effectiveness

Excess Share of Voice (ESOV)

Source: John Philip Jones (1990) / Les Binet & Peter Field
The Empirical Rule

When a brand's Share of Voice (SOV) is greater than its Share of Market (SOM), it tends to grow; when SOV is lower than SOM, it tends to shrink.

What Most Marketers Get Wrong

Setting annual marketing budgets solely as a fixed percentage of last year's revenue without looking at competitor media spend.

Why It Works (The Evidence)

On average across consumer categories, every 10 percentage points of Excess Share of Voice (ESOV = SOV minus SOM) drives roughly 0.5% to 0.7% in annual market share gain, with higher returns for new product launches and strong creative.

How to Apply It on Monday
  • Estimate your current Share of Market and compare it against your Share of Voice in your core category.
  • If your growth target is ambitious, align the board on the required Excess Share of Voice before signing off the budget.
  • Multiply your effective SOV through high-emotion creative, which acts as a force multiplier on media spend.
Law 06 Effectiveness

The 95-5 Rule of Market Readiness

Source: Prof. John Dawes (Ehrenberg-Bass Institute)
The Empirical Rule

Up to 95% of category buyers are not in the market to buy today; only around 5% are actively looking to purchase right now.

What Most Marketers Get Wrong

Expecting advertising to persuade out-of-market people to immediately click and buy today.

Why It Works (The Evidence)

Because purchase cycles in most categories span months or years, advertising works mainly by laying down and refreshing memory structures so that when the 95% eventually enter the market, your brand is one of the two or three they immediately recall.

How to Apply It on Monday
  • Stop judging top-of-funnel media by immediate conversion rate.
  • Maintain continuous media presence across the year rather than blowing the entire budget in a single two-week burst.
  • Ensure your brand is famous and mentally available before the buyer ever types a search query.
Law 07 Brand Growth

The Duplication of Purchase Law

Source: Andrew Ehrenberg / Goodhardt
The Empirical Rule

Every brand shares its customer base with other brands in direct proportion to each competitor's market share.

What Most Marketers Get Wrong

Believing your brand sits in an isolated niche and only competes with one 'direct' lookalike rival.

Why It Works (The Evidence)

Empirical purchase data shows that your customers are repertoire buyers who mostly also buy the largest brands in the category. Even luxury or 'niche' brands share far more customers with the mass-market leader than with other small niche brands.

How to Apply It on Monday
  • Benchmark your brand against the largest category leaders, not just small lookalike competitors.
  • Design your product range and messaging to appeal to the broad mainstream category buyer.
  • Avoid over-segmenting your audience into tiny personas that restrict your reach.
Law 08 Behavioural Science

Costly Signalling & Psychological Value

Source: Rory Sutherland (Alchemy) / Amotz Zahavi (Signalling Theory)
The Empirical Rule

The trustworthiness and perceived prestige of a brand message are directly proportional to the visible cost and commitment required to send it.

What Most Marketers Get Wrong

Assuming a hyper-targeted, zero-cost digital message carries the same psychological weight as a public, high-investment broadcast campaign.

Why It Works (The Evidence)

Just as wedding invitations are printed on heavy card rather than sent via text message, consumers subconsciously infer product quality and business longevity from visible advertising investment (TV, outdoor billboards, sponsorships, physical packaging).

How to Apply It on Monday
  • Use public, shared media (OOH, broadcast, print, events) when you need to build rapid trust and brand stature.
  • Invest in tangible customer touchpoints (unboxing, tactile quality, customer service speed) that signal long-term commitment.
  • Look for psychological solutions to commercial problems alongside purely rational or operational ones.
Law 09 Behavioural Science

The Pratfall Effect & Behavioural Biases

Source: Elliot Aronson (1966) / Richard Shotton (The Choice Factory)
The Empirical Rule

A brand or person becomes significantly more likeable and believable when they openly admit a minor weakness that reinforces their core strength.

What Most Marketers Get Wrong

Claiming your product is flawless, fastest, cheapest, and best at everything.

Why It Works (The Evidence)

Consumers have a finely tuned radar for corporate bragging. Iconic campaigns such as Guinness ('Good things come to those who wait' for a slow pour), Avis ('We're number two, so we try harder'), and Marmite ('Love it or hate it') use a strategic flaw to make their core claim undeniable.

How to Apply It on Monday
  • Identify a trade-off inherent in how your product is made (e.g. higher price, slower craftsmanship, acquired taste) and own it proudly.
  • Pair social proof ('Most popular choice') and concretisation (specific, vivid numbers instead of vague claims) in your copy.
  • Make desired customer behaviours effortless by changing the default option.
Law 10 Behavioural Science

Broad-Beam Attention (Right-Brain Creative)

Source: Orlando Wood (Lemon & Look Out / System1) & Prof. Iain McGilchrist
The Empirical Rule

Advertising that appeals to broad-beam right-brain attention (human characters, humour, dialogue, melody, sense of place) builds far more market share than narrow left-brain product checklists.

What Most Marketers Get Wrong

Filling adverts with fast-cut text overlays, abstract jargon, rhythmic percussion, and relentless feature lists.

Why It Works (The Evidence)

Combining IPA Effectiveness data with System1 emotional testing, Orlando Wood showed that as advertising shifted towards flat, literal, left-brain formats over the last 15 years, creative effectiveness fell, whilst brands using characters, story, and humour consistently outperformed.

How to Apply It on Monday
  • Feature living characters, human interaction, warmth, and cultural familiarity in your creative work.
  • Show the human drama before the product solution, and end with a clear, memorable brand resolution.
  • Test creative for emotional resonance (Star Rating) and rapid brand recognition (Spike Rating) before spending media budget.
Law 11 Commercial Strategy

Pricing Power & Price Elasticity

Source: Mark Ritson / Dr. Grace Kite / Les Binet
The Empirical Rule

One of the largest commercial returns of brand building is reducing price elasticity, allowing a business to defend or raise prices without losing volume.

What Most Marketers Get Wrong

Treating marketing solely as a volume-driving promotion department whilst ignoring the other 3 Ps (Product, Price, Place).

Why It Works (The Evidence)

Econometric studies repeatedly prove that a 1% improvement in realised price has a far greater impact on operating profit than a 1% increase in sales volume, and strong brand equity is the primary driver of low price sensitivity.

How to Apply It on Monday
  • Track price elasticity and average realised selling price alongside volume growth.
  • Avoid habitual discounting, which trains customers to wait for promotions and erodes brand equity.
  • Use brand marketing to justify your price premium before competitors force a race to the bottom.
Law 12 Commercial Strategy

Strategy as Integrative Choices

Source: Prof. Roger Martin & A.G. Lafley (Playing to Win)
The Empirical Rule

Strategy is not a 100-page wish list of goals; it is an integrated set of choices defining Where You Will Play and How You Will Win.

What Most Marketers Get Wrong

Confusing operational planning ('We will launch a new website and post 4 times a week on LinkedIn') with actual strategy.

Why It Works (The Evidence)

True strategy requires choosing what NOT to do. If the opposite of your strategic statement sounds completely absurd on its face (e.g. 'We want to be customer-centric'), then it is a platitude, not a strategic choice.

How to Apply It on Monday
  • Test every strategic statement by asking: 'Does the exact opposite of this choice also make sense for a competitor?' If not, rewrite it.
  • Align five cascading questions: Winning Aspiration, Where to Play, How to Win, Core Capabilities, and Management Systems.
  • Complete thorough diagnosis (market research and segmentation) before touching tactical execution.