Promotions: Measuring Incremental Revenue,
not the volume displaced

Ludovic Shum

Sales Director

September 9, 2026

A promotion that moves more volume doesn't necessarily create more value: part of that volume already existed. According to Nielsen, 58% of promotions in France result in a loss, and promotions now account for 21.9% of FMCG sales in 2025—a 20-year high. Measuring this incremental impact on a product-by-product basis is the purpose of BOOPER’s Promotion Management module.

A promotion that generates twice as much sales volume does not necessarily create twice as much value. Part of that volume already existed: customers who would have bought the product anyway, a little sooner or a little later, at another store, or as a similar product.

This guide explains how to distinguish between truly incremental sales and sales that have simply shifted, and how to measure that difference without a complex testing lab.

Table of Contents

H2 Headings

Promotional price tags above a shelf; shaded portion = non-incremental volume

The volume trap that hides the real issue

In most sales teams, a promotional campaign is judged by a single metric: the volume sold during the period. The higher the sales, the more successful the campaign is considered to be.

This assumption raises a simple problem: total volume says nothing about what the promotion actually generated. Of the 100 units sold during the promotion, some would have been purchased anyway, others were simply bought earlier than planned by customers who stocked up, and still others came from a nearby store of the same chain or a competing product in the same aisle. What remains, once these portions are accounted for, isthe actual increment —the only part that economically justifies the cost of the promotion.

Celebrating gross volume is tantamount to confusing shifted revenue with growth. It is precisely this bias that explains why a promotion can show a dramatic increase in sales while, at the same time, eroding margins over the entire period.

Incremental vs. Offset: The Distinction That Changes Everything

Incrementality measures the portion of sales that would not have occurred without the promotion —neither on that date, nor in that store, nor for that product. Everything else is shifted volume: it already existed somewhere in the system; the promotion simply brought it to light at a different point in the schedule or on the shelf.

Incremental

A sale created

A customer who would not have purchased this product at that time without the offer — new net revenue.

Moved

A sale moved up or postponed

A purchase that would have taken place anyway, but was simply brought forward or postponed.

This distinction is not merely theoretical: it determines whether the cost of the discount offered is a profitable investment or a pure loss disguised as commercial success.

The 3 Leaks That Inflate Volume Without Creating Value

The non-incremental volume of a promotion can be broken down into three distinct mechanisms, each of which must be examined separately to understand where value is actually being lost.

Leak	Mechanism	How to limit it
Deferred Purchase	Regular customers make their purchases or stock up when a sale is on, and then don't buy anything for several weeks.	Track sales over a broader period after the promotion, not just during it.
Store Report	A customer switches to a different store within the same chain to take advantage of the offer, without making any additional net purchases.	Compare sales at the store running the promotion with those at neighboring stores of the same chain.
Intra-category cannibalization	The promoted item captures sales that would otherwise have gone to a similar variant or format in the same aisle.	Measure sales trends for the entire category, not just the promoted item.

A fourth type of customer loss, which is rarer but still real: customers switching from a competing brand to yours. This is the only one of the four that’s positive for you—but negative for the industry as a whole.

Our article on cross-elasticity, cannibalization, and the halo effect details the statistical mechanism behind the third leakage.

58% of promotions result in a loss: the real figure

This is not a minor issue. A Nielsen study analyzing 76 million promotional campaigns across 7 countries (the United States, United Kingdom, Germany, France, Italy, Spain, and Canada) measured the true scale of the phenomenon as early as 2014—and there is no indication that the trend has reversed since then, as measuring incremental impact remains, for most retailers, a blind spot rather than a systematic practice.

58%

Promotions carried out in France result in losses for the brands that fund them—a rate close to the global average (60%), but higher than that observed in Spain, Germany, Canada, and Italy (Nielsen, Trade Promotion Performance, a study covering 76 million promotions in 7 countries, 2014).

The same study reveals a significant performance gap: the top 10% of promotions in terms of profitability generate a return seven times greater than that of the bottom 10%. The problem is not promotion as a strategy—it is the almost systematic lack of measurement that makes it impossible to determine, in advance, which promotions will fall into which group.

The record number of graduates in France in 2025

This observation takes on particular significance at a time when promotions are playing a more significant role than ever in the French retail sector. After two years marked by high inflation followed by a trend toward disinflation, retailers have made promotional offers a key strategy for maintaining their appeal.

21.9%

of FMCG sales in hypermarkets and supermarkets came from promotional sales in 2025 —a record share over the past 20 years. At the same time, 45% of French households now report trying to buy on sale, up 2 percentage points (NielsenIQ, 2025 FMCG Market Outlook, report published in 2026).

The larger the share of revenue accounted for by promotions, the more critical it becomes to measure their actual incremental impact: at this volume level, even a few points of measurement error represent significant margin amounts, which accumulate week after week across the entire network.

Measuring Incremental Systems Without a Test Lab

Measuring incremental impact does not require the resources of a marketing research lab. Three approaches—which can be combined—are sufficient to obtain a reliable estimate: a control store or area that does not receive the promotion and serves as a benchmark; an extended measurement window before and after the campaign to detect deferred purchases; and an analysis at the category level to isolate intra-category cannibalization.

These three analyses require detailed, granular sales history—by SKU, by store, by week—and an elasticity model capable of calculating a credible baseline: what would have been sold without the promotion. Without this baseline, any measure of incrementality remains nothing more than a rough estimate.

At Booper

Understand the impact before committing to the promotional budget

GENIUS Predict calculates a sales baseline by SKU and by store, then simulates the expected impact of a promotion on demand and inventory before its launch, taking into account cross-elasticities and cannibalization effects already identified within the category.

GENIUS Promotions then manages the execution of the campaign according to the defined business rules, while GENIUS Monitoring tracks in real time any discrepancies between the projected sales trajectory and actual sales.

Learn more about the platform on our MPS page : Booper, the modular pricing solution.

How many of your promotions are actually profitable?

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FAQ

Incrementality measures the portion of sales generated during a promotion that would not have occurred without it. The rest of the volume—often the majority—consists of sales that already existed elsewhere, either before or after the promotion, or at a competitor’s store.

By comparing actual sales to a baseline (what would have been sold without the promotion), and then isolating the shift in purchase timing, the shift in store choice, and intra-category cannibalization. The amount that exceeds these components is the actual increment.

According to Nielsen, 58% of promotions result in losses in France. The most common cause is the failure to measure actual incremental sales, not the concept of promotions itself.

No. No promotion is ever 100% incremental. The goal is to determine where each campaign stands in order to make informed decisions, not to reach a theoretical threshold.

The most accessible method remains the store or test area, combined with its own sales history and an elasticity model to calculate a reliable baseline.

Cannibalization is one of the causes of non-incrementality, not the other way around: the volume taken from a neighboring SKU in the same store. Purchase deferral and store deferral are two other distinct causes.

Also in this series

Sources: Nielsen, Trade Promotion Performance, a study of 76 million promotional campaigns in 7 countries, 2014 · NielsenIQ, 2025 Consumer Goods Market Outlook, report published in 2026 · Booper, internal product data (GENIUS Predict, GENIUS Promotions, GENIUS Monitoring)

Promotions: Measuring Incremental Revenue, not the volume displaced