Elasticidade de Preço: quando vender mais significa crescer menos

The meeting starts well. The retailer accepted the plan, sell-out went up, the weekly curve looks clean, and someone opens the dashboard as if the argument has already been won. The product sold 38% more units with a 20% discount. The room relaxes. The volume target looks closer.

Then comes the question that ruins the mood and saves money: how much of that volume bought real growth?

If the answer fits into one dashboard line, it is probably incomplete. More units sold for a few days can mean higher penetration, a purchase pulled from next month, temporary brand switching, inventory sitting at home, or lower margin dressed up as traction. Price elasticity forces the company to separate those effects.

This recalls another measurement trap. In media, viewability can look like proof of attention while measuring something else, as I argued in Viewability does not measure attention. In pricing, volume can look like proof of growth while measuring movement. Movement can be healthy, or anxiety captured as sales.

Higher volume does not prove that the brand grew

The most expensive belief in commercial marketing is simple: if it sold more, it worked. It survives because it feels comfortable. Volume arrives fast, fits quarterly targets, and creates a sense of control. But brand growth lives in a longer period: how many people buy, how often, at what margin, with which reference price, and with what willingness to pay next time.

Byron Sharp and the Ehrenberg-Bass Institute argue in How Brands Grow that loyal buyers also buy competitors and that price promotions rarely bring many new buyers into the category. Promotions often activate people who would already buy, people who would buy later, or people willing to switch for price. The risk sits in shallow interpretation: giving strategic credit to a sale that may have been merely opportunistic.

A promotion can raise the pile of units sold and reduce the economic quality of that sale. The dashboard smiles before the income statement speaks. Diego Isaac

Robert Blattberg, Richard Briesch, and Edward Fox organized this anatomy well in their work on how promotions work. Promotional response can come from brand switching, purchase acceleration, larger baskets, and stockpiling. Each effect has a different value. Winning a new household for the brand is one thing. Selling today the pack that would have been bought three weeks from now is another.

Price elasticity in meeting language

Price elasticity is the relation between a price change and a demand change. If price falls 10% and volume rises 20%, demand reacted strongly. If price rises 5% and volume barely moves, the brand has more protection. The formal calculation matters, but the executive question is simpler: how much volume appears or disappears when we change price?

The common error is treating that reaction as a fixed property of the product. Elasticity changes by channel, occasion, competition, discount depth, communication, availability, pack, income, household inventory, and brand strength. A brand with mental and physical availability tends to suffer less when it needs to hold price. Les Binet and Peter Field, through IPA effectiveness work and The Long and the Short of It, show from another angle that brand building supports growth, reduces dependence on activation, and helps defend price.

Thomas Nagle, John Hogan, and Joseph Zale, in The Strategy and Tactics of Pricing, treat price as a strategic decision about value capture. Price connects cost, competition, perceived value, and offer design. When the company turns price into an emergency button, the value-capture conversation becomes a race to close the month.

Hendel and Nevo, in Sales and Consumer Inventory, show that consumers buy into inventory when price drops. If the model sees only the promotion week, price appears to create a large amount of demand. Once the pantry enters the analysis, part of that demand is timing. The brand may have brought revenue forward with lower margin.

The calculation that must appear before the discount

A mature analysis separates five lines.

Volume answers how many units moved. It helps with capacity, negotiation, and short-term share. By itself, it leaves margin outside the room.

Revenue shows gross money. It can grow less than volume when the discount eats average price. In some cases, it rises for a few days and then falls because consumers bought ahead of time.

Margin shows what remains. An action that raises volume and reduces absolute margin needs a very clear reason: new penetration, competitive defense, inventory rotation, pack test, channel entry, or measured learning.

Advanced inventory is the purchase taken from the future. Pauwels, Hanssens, and Siddarth, in the Journal of Marketing Research, analyze the effects of promotions on category incidence, brand choice, and purchase quantity. The reading becomes more honest when the company asks whether the category grew, whether the brand was chosen by more people, or whether the basket temporarily became larger.

Incremental purchase is the part that justifies the risk. Incrementality asks what would have happened without the discount. Without a counterfactual, the discount receives credit for sales that may have happened anyway.

Vincent Nijs, Marnik Dekimpe, Jan-Benedict Steenkamp, and Dominique Hanssens, in Marketing Science, studied category-demand effects of price promotions. The practical message is uncomfortable: not every promotional spike expands the category over time. Much apparent growth is redistribution across time or between brands.

Promotion also trains the consumer

The company thinks it is training the channel. Often, it is training the consumer. If the brand goes on deal every month, full price becomes a temporary suggestion. Consumers, retailers, and commercial teams learn to wait for funds. Later, the company calls this a price-sensitive market.

Carl F. Mela, Sunil Gupta, and Donald R. Lehmann, in the Journal of Marketing, studied the long-term impact of promotion and advertising on brand choice. Their evidence helps treat the subject with less innocence: promotion and advertising change consumer response to the marketing mix over time. The history of stimuli changes what happens in the next campaign.

This is the link with Price promotions: marketing’s expensive addiction. The cost of a weak promotion rarely ends in the action week. It returns as demand for funds, erosion of reference price, and less patience for building preference.

Kusum Ailawadi, Donald Lehmann, and Scott Neslin proposed revenue premium as a measure of brand equity. The logic is useful: a strong brand should generate more revenue than a generic or less preferred alternative, combining volume and price. When a brand only grows with discounts, its supposed equity deserves an audit.

A simple framework for deciding on a discount

A discount can be a good tool. The problem is using it as anesthesia. Before approving an action, I would split the decision into six questions.

The question about pack architecture deserves its own attention. Sometimes the answer is less about cutting price and more about redesigning access. Smaller packs, entry units, multipacks, premium versions, bundles, and usage occasions can protect average price while widening penetration. That is the subject of Price Pack Architecture: brand penetration and accessibility.

Mary Kyriakidi from Kantar wrote in 2024 about marketers and consumer sensitivity to price changes. The practical conclusion is strong: pricing must be jointly stewarded by marketing and finance. Finance protects value capture. Marketing protects the reason consumers accept paying.

What elasticity hides when it becomes an average

Average elasticity looks technical and neutral, but it often hides very different pockets of behavior. The buyer who already planned to buy reacts in one way. The buyer who was with a competitor reacts in another. The buyer who takes three units for the pantry reacts in another. The retailer sees the aggregate curve and reads one response. The brand needs to look beneath that curve.

A 20% discount can produce three stories at the same time. The first is healthy: occasional buyers enter, try the brand, and some return without a stimulus. The second is neutral: habitual buyers purchase earlier, increase the basket, and leave a gap in the following weeks. The third is damaging: opportunistic buyers take the brand for the price and return to any competitor in the next deal. The volume dashboard merges the three stories as if they were one.

That is why the elasticity question must move from the average into cuts. Which channel reacted? Which region? Which pack? Which discount depth? Which competitor was active? What was the level of distribution? Did the promotion reach low-frequency shoppers or concentrate heavy buyers? The answer decides whether the company learned something about demand or paid to accelerate a predictable sale.

This reading also protects the team from confusing category sensitivity with brand weakness. Some categories have price-aware consumers because the purchase is frequent, comparable, and visible in the household budget. Others suffer less because perceived risk, habit, or convenience weighs more. Within the same category, brands with higher mental availability, recognizable distinctive assets, and wider physical presence tend to arrive at the shelf with an advantage: the consumer needs less effort to choose them.

The elasticity that matters to management, then, combines economics and memory. If the brand only appears when it cuts price, the problem may sit before price. It may sit in weak salience, thin distribution, packaging that is hard to recognize, poorly coded usage occasions, or offer architecture. Changing price without fixing those bases turns a symptom into strategy.

How to measure without buying an illusion

The minimum method is to compare equivalent stores, regions, or periods with and without promotion. A better method uses experiments, control groups, history, seasonality, competition, media, distribution, and stockouts. The question remains the same: what happened because of the discount, and what would have happened without it? That question separates observed sales from incremental sales.

The post-promotion period deserves the same discipline used in the action week. If the curve rises during promotion and falls afterward, part of the gain was borrowed. If repeat without discount improves, there is a favorable learning signal. If average price falls for several weeks, the brand may have changed the reference price. If the retailer demands the same funds next month, the action created commercial dependence.

Another useful metric is margin per incremental buyer. It forces the team to stop celebrating every unit in the same way. Ten thousand units sold to buyers who would have bought anyway may be worth less than two thousand units sold to new households, if those households return later. The reverse also happens: an acquisition promotion can sound noble and still destroy value if it buys attention from people with little chance of repeating.

The company also needs to separate tactical discounting from pricing policy. A tactical discount has an objective, a window, control, and a post-read. Pricing policy in disguise appears when the exception becomes the calendar. Full price loses credibility. The commercial team starts negotiating from future funds. Consumers learn the game. At that point, observed elasticity has been partly manufactured by the brand itself.

The best signal of strength appears when the brand loses little while holding price, gains penetration without crushing margin, and uses promotion as a punctual instrument inside a broader system. A strong brand lives with price sensitivity, but gives the company more degrees of freedom to decide when price should be a lever and when it should be protected.

When a discount makes sense

The point is not to treat every promotion as a mistake. There are legitimate uses. A brand can use a discount to accelerate trial when entering a new channel, reduce the entry barrier for an unfamiliar pack, defend space in a specific competitive window, clear inventory with a defined deadline, or test response across comparable groups. The difference is discipline. The action starts with a hypothesis, a limit, a read, and a consequence.

The danger appears when discounting replaces diagnosis. If distribution is low, the primary answer may be presence. If distinctive assets are weak, the answer may be recognition. If the entry pack is too expensive, the response may be architecture, not a cut on the main product. If communication fails to build memory, lowering price only buys attention for a week. Each problem asks for a different lever.

There is also an important difference between accessibility and discounting. Accessibility means designing ways in that expand buying without damaging value logic. Discounting reduces capture on the same product. A sachet, a smaller version, an entry plan, a bundle with a clear role, or a mechanic tied to an occasion can open the door to new buyers while preserving the reference of the main item. That choice connects with strategy. Recurring discounting connects with urgency.

A useful practical rule is to require every promotion to answer two questions before receiving funds. First: which behavior do we want to create that continues after the action? Second: which indicator will prove that this behavior appeared? If the answer is only to sell more units this week, the company is buying movement. That may be necessary in some moments, but it should be named correctly: trading margin for cash or rotation. Brand growth demands a higher bar.

This rule also changes the tone of the meeting. The discussion moves from defending a discount to defending a business case. The team can still choose price as the lever, but the choice carries a reason, a measurement plan, and a definition of success beyond the week of the spike.

The practical implication

When a discount wins a meeting, ask for a second screen. The first one shows volume. The second one must show margin, average price, new buyers, repeat behavior, estimated inventory, post-action behavior, and the effect on reference price.

If the promotion brought new people, protected margin, and generated repeatable learning, good. If it pulled purchase forward and taught consumers to wait, the growth was borrowed from the future, with interest.

Price elasticity marks the point where marketing stops treating sales as a count and starts treating it as demand quality. Growth requires more than moving units. It requires selling in a way that preserves willingness to pay tomorrow.