# Promotional incrementality

Promotional incrementality is the share of sales during a promotion that would not have happened without it.

Also called: incrementality, promo incrementality

- **Is:** The share of promotional sales that would not have happened without the promotion.
- **Subtract:** Baseline sales, sales pulled forward from later weeks, and sales switched from other lines.
- **Watch for:** Judging a promotion on promoted units alone. It always looks like a win.

## What it means for retail and category teams

A promotion's volume is made up of new sales, sales pulled forward from future weeks as shoppers stock up, sales switched from other products the retailer sells, and sales it would have made anyway at full price. Incrementality isolates the first. Measuring it means estimating a baseline of what would have sold without the promotion, then accounting for the dip afterwards and the effect on neighbouring lines.

## Why it matters

A promotion judged on promoted units alone will always look successful. Once pull-forward, cannibalisation and the discount on sales that would have happened anyway are counted, many promotions add little or cost margin. Incrementality is what separates the promotions worth repeating from those that only rearrange demand.

## Illustrative example

The business and figures are illustrative. None of it is customer data.

A pasta sauce normally sells 1,000 units a week. During a half-price week it sells 3,000. The following week it sells 600 as shoppers use up their stock, and a rival sauce the retailer stocks drops by 500 units during the promotion. Of the 2,000 extra units, about 400 were pulled forward and 500 switched from the rival, leaving 1,100 incremental units, all sold at half price.

**Pasta sauce: the 2,000 extra units in a half-price week**

- Pulled forward from next week: 400
- Switched from a rival sauce: 500
- Incremental: 1,100

Just over half the extra volume is new, and all of it sold at half price.

## Related concepts

- [Cannibalisation](https://twelfth.ai/glossary/cannibalisation): Subtract sales shifted from neighbouring lines before claiming a category gain.
- [Markdown](https://twelfth.ai/glossary/markdown)
- [Category management](https://twelfth.ai/glossary/category-management): Judge the promotion on the category total as well as the promoted SKU.
- [Demand forecast](https://twelfth.ai/glossary/demand-forecast)

## Next step

### Look at the price gaps that matter

Bring a few products and competitors. We can walk through matching, observation dates and which gaps deserve a closer look.

- [Book a demo](https://twelfth.ai/book-a-demo)
- [twelfth for merch analysts](https://twelfth.ai/for/merch-analysts): Price, promo, range and space read off one line, with promotion results back before the next deal sheet is committed.

Source: https://twelfth.ai/glossary/promotional-incrementality