Cross-elasticity, cannibalization, halo effect
Fabrice Decroo
Consulting Director
August 16, 2026
A price change results in both cannibalization (of substitute products) andthe halo effect (on complementary products). Ignoring this mechanism is equivalent to measuring only half of the actual impact of a pricing decision.
On average, 22% of the increase in sales of a product on promotion comes from a simple shift from other SKUs in the same product line.
Lowering a product's price does more than just alter its own sales: it shifts demand toward—or away from—other references in your catalog. This transfer has a name: cross-price elasticity, and two faces: cannibalization, which internally destroys value, and the halo effect, which creates it. Ignoring this mechanism means managing a price as if it exists in isolation on the shelf.
Three effects, a single phenomenon
Classic price elasticity answers a simple question: if I change the price of product A, how do the sales of product A vary? Cross-price elasticity asks a more disruptive question: if I change the price of product A, how do the sales of product B vary?
The answer has a sign, and that sign changes everything:
- Positive sign → substitutes. Two plain yogurts from different brands. Lowering the price of one mechanically drives down the sales of the other: this is cannibalization.
- Negative sign → complements. A coffee machine and its capsules. Lowering the price of the machine can increase the sales of capsules: this is the halo effect.
The same price change therefore simultaneously produces cannibalization on certain references and a halo effect on others. Managing a price without considering these two effects means measuring only half of the real impact of a decision.
Cannibalization: when a price eats into the sales of another
Cannibalization is not a rare accident — it is the default behavior of an improperly isolated promotion. A study published in an academic journal (ScienceDirect) on the effects of promotions in mass retail shows that, on average, 22% of the sales increase generated by a promoted format comes from other formats of the same product — not new customers, just a volume shift within the same portfolio.
of a promoted product's sales increase comes on average from other formats of the same product, not new sales — a volume shift, not value creation (ScienceDirect study on mass retail promotions).
In high-substitution categories (yogurts, laundry detergents, mineral waters), the phenomenon goes further. According to revenue growth management practitioners, a cannibalization rate of 15 to 35% is common in fast-moving consumer goods — and beyond 50%, the promotion merely shifts volume between its own references at a loss, without capturing a single euro of new demand.
The trap: this figure never appears in a standard sales report. A 12% increase on the promoted product looks like a success — until you look at the two neighboring references that each lost 8% at the same time.
Halo effect: when a price drop benefits others
The halo effect is the positive mirror image of cannibalization. It appears between complementary products — where purchasing one makes purchasing the other more likely or more necessary:
- A printer and its ink cartridges.
- A barbecue and charcoal.
- A capsule coffee machine and the capsules themselves.
Lowering the loss-leader price (such as a printer or a machine) can generate more margin on the complementary product (cartridges or capsules) than the price reduction itself cost. This is one of the rare cases where aggressive pricing is justified by data, rather than just marketing intuition.
How to Read a Cross-Price Elasticity Coefficient
The reading principle remains simple once you have the sign and the order of magnitude:
- High positive coefficient: strong substitution. A price cut on product A will erode a significant share of product B's sales — to be treated as a trade-off, not a net gain.
- Low positive coefficient: moderate substitution. Both references largely coexist, and the cross-impact remains manageable.
- Negative coefficient: complementarity. A signal to leverage when building bundles or calibrating a loss-leader price, rather than something to correct.
- Coefficient close to zero: both products live virtually independent lives — rare in reality, except for categories very far apart in the catalog.
The most frequent mistake is not misreading a coefficient: it is never calculating it, and treating each reference as if it existed in isolation within the catalog — see also our article on how to interpret price elasticity.
How to spot these effects in your own catalog
Map high-risk pairs
Identify references that share an aisle, a use case, or a customer need (such as similar yogurts, or machine + consumable) even before looking at the data.
Analyze historical cross-promotional data
Examine what happened to neighboring references during past promotions at the same time — not just the promoted reference.
Isolate the true signal from noise
Neutralize seasonality, out-of-stock events, and weather effects before concluding that a sales movement stems from a cross-elasticity effect.
Document continuously, don't just calculate once
Product relationships evolve alongside the assortment. A coefficient measured a year ago may no longer reflect the reality of the current catalog.
A real-world case study: Coopérative U
At Coopérative U, the deployed platform combines sales forecasting, simple and cross-price elasticities, and cannibalization detection within a single pricing recommendation engine — rather than treating each reference in isolation. The stated objective was not merely to set the right price, but to secure a triple objective simultaneously: margin, competitiveness, and price image. A price that increases margin while cannibalizing two neighboring references at a loss fails to meet this objective — even if it appears to do so on an isolated report.
Before validating a price reduction
- Have I identified the substitutable references that could lose sales?
- Have I identified the complementary references that could gain sales?
- Is the net impact (direct gain − cannibalization + halo effect) positive, rather than just the direct gain?
- Has this coefficient been recalculated recently, or has it been sitting unused in a spreadsheet for a year?
FAQ
The questions we are most frequently asked before getting started.
Simple elasticity measures the effect of a product's price on its own sales. Cross-elasticity measures the effect of a product's price on the sales of another product in the catalog.
The sign of the cross-elasticity coefficient provides the answer: positive indicates substitutes (potential cannibalization); negative indicates complements (potential halo effect).
Not necessarily: cannibalizing a low-margin reference in favor of a high-margin reference can be a deliberate goal. The issue arises when it goes unidentified and distorts the assessment of a promotion's success.
By identifying loss-leader and complementary product pairs, and calibrating the loss leader's price not to maximize its own margin, but the combined margin of both references.
No. Focusing first on high-stakes pairs (high volume, close usage, or category proximity) delivers the majority of value for a reasonable effort.
Advanced pricing analytics tools model both simple and cross-elasticities based on historical sales data, but the quality of the output depends directly on the quality and depth of the available data.
Sources: Estimating cannibalizing effects of sales promotions, Journal of Retailing and Consumer Services (ScienceDirect) — sciencedirect.com · RGM Academy, “Cannibalization Rate” — rgmacademy.app · Business Case Booper × Coopérative U (customer case study published by Booper).
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