The rule your marketing plan is built on does not hold
Eighty percent of sales come from twenty percent of customers. It is in the textbooks, the pitch decks, and the segmentation slide of almost every marketing plan.
In marketing it is closer to 60/20. Sharp, Romaniuk, and Graham put the brand average contribution from the heaviest 20% of buyers at around 59%.
The finding is not confined to one institute. Brynjolfsson, Hu, and Simester examined women's clothing retail in 2011 and titled their conclusion "Goodbye Pareto Principle." Romaniuk and Sharp replicated across grocery categories in India, Malaysia, Kenya, and Mexico in 2016. Steenkamp reached similar conclusions in 2017. Reported results cluster between 50/20 and 65/20. Schmittlein, Cooper, and Morrison had questioned the concentration assumption in Marketing Science as early as 1993.
The Indian replication matters for anyone reading this from a domestic market. These are not findings from Western packaged goods alone. The pattern holds in developing markets and in categories that behave nothing like detergent.
Then it gets worse for the loyalty plan.
Heavy buyers do not stay heavy
The 60/20 figure is backward-looking, and marketing plans are forward-looking.
The institute's own position is that even 60/20 overstates the case for planning purposes. For stable brands, around half of this year's heaviest 20% of buyers will not qualify as heavy buyers next year. Meanwhile, people who were light or non-buyers this year will contribute more next year than they did this one.
This is statistical regression, not disloyalty. Someone who bought your product six times last year did so partly through circumstance — a period of higher need, a run of convenient availability, a household change. Circumstances revert.
The practical consequence is direct. A retention strategy built around this year's heavy buyers targets a group that is, by measurement, about to shrink in value. The light and non-buyers it ignores are the group about to grow.
The laws, briefly
Double jeopardy. Smaller brands are penalised twice — fewer buyers, and slightly lower loyalty from those buyers. First observed by McPhee in 1963, formalised by Ehrenberg, Goodhardt, and Barwise in 1990.
The replication record is why this is the strongest evidence in the series. Double jeopardy has been found in packaged goods, retail banking, insurance, luxury goods, political voting, car buying, concrete supply, airline purchasing, and newer categories including music streaming and ride-hailing. Romaniuk and Wight tested it across 60 brands in 10 categories and 7 countries.
The implication: loyalty is not an independent lever. It moves with penetration. A brand with low loyalty relative to its size has a penetration problem, and a loyalty campaign is the wrong instrument.
Duplication of purchase. Your buyers also buy competitors, in proportion to those competitors' market share. You do not have a distinct tribe. You share customers with everyone in the category, and you share most with the biggest players.
Natural monopoly. Larger brands attract a disproportionate share of light category buyers. Small brands are bought mostly by heavier category buyers, which is the opposite of how most small brands describe themselves.
Limited segment differences. Competing brands' user bases look more similar than different on most measures. The distinct customer profiles in segmentation decks usually describe variance that does not survive proper analysis.
What follows practically
Reach category buyers broadly. Growth comes from penetration — more people buying, most of them rarely. Narrow targeting optimises against the mechanism.
Build mental availability. Being thought of in the buying situation, across as many buying situations as possible. This is the growth lever the laws point to most directly.
Build physical availability. Being easy to find and buy. Distribution, shelf presence, search visibility, checkout friction. Unglamorous and frequently the binding constraint.
Use distinctive assets, not differentiation claims. Buyers rarely perceive the differences brands invest in. What works is being recognisable — colours, logos, characters, sonic cues, packaging shapes — so attention converts to identification.
Do not neglect the light buyers. They deliver almost half of current sales and most of the growth.
The evidence, and its complications
Empirically grounded. This is the best-replicated body of work in the series: multiple institutions, multiple countries, multiple decades, published in peer-reviewed journals, independently reproduced.
Three complications worth stating.
Funding. The Ehrenberg-Bass Institute is supported by corporate sponsors including large advertisers, and much of its detailed work is published as sponsor reports rather than in journals. The independent replications matter partly because of this.
Tone. Sharp's engagement with critics is combative and frequently dismissive — describing objections as thinly disguised advertisements for consulting services. That is a fair reading of some criticism and not of all of it. It also makes the literature harder to navigate than it should be.
The differentiation question. The strong reading — that differentiation does not matter — goes further than the data requires. What the evidence shows is that buyers perceive far less differentiation than marketers believe, and that distinctiveness does more work than differentiation. That is a meaningful claim without being the absolute one it is often reported as.
None of this changes the core findings. It does mean the laws should be applied as well-evidenced regularities rather than received doctrine.
Where the laws get misread
"Positioning does not matter." The laws describe how buyers behave within a category. They do not say a business should skip deciding what it is and who it serves. A brand that cannot be described cannot be made mentally available.
"Never talk to existing customers." The finding is that loyalty is not an independent growth lever, not that service and retention are worthless. Retention protects the base; penetration grows it.
"Segmentation is useless." The finding is that competing brands' user bases differ less than assumed. Segmentation for media buying, for product decisions, or for operational reasons can still be sound.
"This is only for large FMCG brands." The replication set includes B2B services, durables, luxury, and developing markets. Small brands are affected more, not less — double jeopardy is specifically a description of what small brands face.
"So we should just buy reach." Reach without distinctive assets produces attention nobody attributes to you. The laws work together.
Diagnostic: is the plan aligned with the evidence?
Seven tests.
The growth target is expressed in penetration, not in loyalty or frequency.
The plan reaches category buyers broadly rather than a narrow segment.
Distinctive brand assets are defined, consistent, and measured for recognition.
Physical availability has been audited — where buyers look, and whether you are there.
Budget is not concentrated on existing heavy buyers.
The segmentation in use has been checked for whether the segments actually behave differently.
Somebody can state what proportion of category buyers have never bought from you.
Test seven is usually the uncomfortable one. For most brands the answer is the overwhelming majority, and that is where the growth is.
What this produces
A growth plan aimed at the mechanism that actually produces growth.
That is the whole contribution, and it is larger than it sounds, because the default plan aims elsewhere. Loyalty programmes, narrow targeting, and heavy-buyer retention all feel efficient and all optimise against a group with limited headroom that is statistically about to shrink.
The laws are not a strategy. They describe the terrain any strategy operates on. A business can still choose where to compete and on what basis — but a plan that assumes buyers are loyal, distinct, and concentrated is planning for a market that the evidence says does not exist.
Frequently asked questions
Is the 80/20 rule true in marketing?
No. Research puts the heaviest 20% of buyers at around 59% of sales, with replicated results between 50/20 and 65/20 across categories and countries including India, Malaysia, Kenya, and Mexico.
Why is 60/20 still an overstatement?
Because it looks backward. Around half of this year's heaviest buyers will not be heavy buyers next year, through statistical regression rather than disloyalty, while light and non-buyers will contribute more. For forward planning, the case for heavy-buyer focus is weaker still.
Does this mean loyalty marketing is pointless?
It means loyalty is not an independent growth lever — it moves with penetration. Retention protects the base and remains worth doing. It does not grow the brand, and treating it as the growth strategy misreads the mechanism.
What is the difference between distinctiveness and differentiation?
Differentiation is being meaningfully different. Distinctiveness is being recognisable — assets that let buyers identify you quickly. The evidence indicates buyers perceive far less differentiation than marketers assume, and that distinctiveness does more of the work.
Do the Ehrenberg-Bass laws apply to B2B and small brands?
Yes. Double jeopardy has been documented in retail banking, business insurance, concrete supply, and airline purchasing. It applies to small brands especially, since it describes precisely the disadvantage small brands face.
How reliable is this research?
It is the most replicated body of work covered in this series, across institutions, countries, and decades. Two caveats: the institute is corporate-funded with much detail in sponsor reports, and the strong "differentiation does not matter" reading goes further than the data supports.
What should we do differently on Monday?
Find out what proportion of category buyers have never bought from you, check whether your distinctive assets are actually recognised, and audit physical availability. Those three answers usually reset the plan.
Sources
Sharp, B. and Romaniuk, J., There is a Pareto Law — But Not As You Know It (2007); Sharp, B., Romaniuk, J. and Graham, C., Marketing's 60/20 Pareto Law (2019)
Ehrenberg, A., Goodhardt, G. and Barwise, P., on double jeopardy (1990); McPhee, W. (1963)
Brynjolfsson, E., Hu, Y. and Simester, D. (2011); Romaniuk, J. and Sharp, B. (2016), developing-market replications; Steenkamp, J-B. (2017)
Schmittlein, D., Cooper, L. and Morrison, D., Truth in Concentration in the Land of (80/20) Laws, Marketing Science (1993)
Romaniuk, J. and Wight, S., Marketing Letters; Graham, C., Sharp, B., Trinh, G. and Dawes, J., The Unbearable Lightness of Buying
Sharp, B., How Brands Grow (2010); Romaniuk, J. and Sharp, B., How Brands Grow Part 2
Structure your next phase
Zerologic builds growth plans on how categories actually buy — penetration, availability, and distinctive assets — rather than on assumptions about loyalty the evidence does not support.
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