Sales Cannibalization

Cannibalization is one of three effects that separate the extra sales of a promoted item from what the promotion actually added. The post‑promotion dip is a shift in time, as customers bring forward purchases of the same item. Halo lifts sales of complementary products. Cannibalization is a shift between substitutes in the same weeks: another brand, another pack size, the private label version of the same product. It is measured against the baseline each substitute would have sold without the promotion, and its strength between two items is described by cross‑price elasticity.

• Cannibalized sales = Σ (baseline of substitute − actual sales of substitute) over the promotion period
• Cannibalization rate = cannibalized sales / uplift of the promoted item

Sales cannibalization in practice

Cannibalization costs margin even where it costs no units. A customer who normally buys a private label product at 50 with a unit margin of 17.50 switches to a branded product promoted from 80 to 60 with a purchase cost of 54, which leaves a unit margin of 6. The category sells the same number of units and every switched unit costs 11.50. A report built on units of the promoted item records this as a successful promotion. Where the private label carries a higher margin than the brands around it, a promotion on a brand has to bring new units into the category, not just redistribute existing ones.

The estimate is only as good as the cannibalization groups behind it. A group that is too wide, such as a whole category of unrelated items, dilutes the effect into noise; a group that is too narrow misses the substitute customers actually switched to. The same mechanism runs in reverse in assortment decisions: when an item is delisted, part of its sales transfers to the remaining substitutes, so the loss is smaller than its current sales suggest. Replenishment needs it too. If substitutes are ordered to their normal forecast during a promotion, the demand that moved to the promoted item stays on their shelves, and in fresh categories that ends as write‑offs.

Veritico PROMO measures true incremental sales against a calculated baseline, taking cannibalization, halo and the post‑promotion dip into account, and Veritico STOCK accounts for cannibalization within defined cannibalization groups in its promotional forecast. See uplift and cannibalization, promotion forecasting and, for delisting decisions, the RANGE module.

Related terms

• Promotion Effectiveness
• Baseline Demand
• Price Elasticity of Demand
• Halo Effect
• Sales Uplift
• Price Optimization