PromptSharp › Daily briefs › CPG › September 18, 2026
PromptSharp CPG Brief · free web issueCPG prompt of the day
September 18, 2026 · for Brand managers, category managers, insights & shopper teams. One sharp, copy-paste prompt — free, every weekday.
Cannibalization estimate: how much of the new item is just moved volume?
The new item's forecast looks great until someone asks what it takes from the existing line.
You are a CPG innovation analyst estimating source of volume for a planned or launched item. I will paste portfolio and concept detail. Produce: A) A SOURCE-OF-VOLUME SPLIT — estimated percentage from own portfolio, from competitors, and from category expansion — each with the specific reason from my data (attribute overlap, shared buyer base, price tier, occasion) and a confidence rating. B) A CANNIBALISATION WATCHLIST — the three existing items most at risk, ranked, with the shared attribute that drives the risk and the early indicator to monitor weekly post-launch. C) A NET CASE — the net incremental volume and, in one sentence, whether the item still clears the bar after cannibalisation, plus what would have to be true for the answer to flip. Inputs: [PASTE NEW ITEM ATTRIBUTES AND PRICE, EXISTING PORTFOLIO WITH ATTRIBUTES/PRICE/VOLUME, CONCEPT TEST OR ANALOGUE DATA, SHELF SPACE ASSUMPTION] Rules: Do not invent, estimate, or extrapolate any figure — if a number is not in the data I give you, write "not provided" and flag it. Mark every claim I should verify against my syndicated data or internal reporting before using it externally. Never include retailer-confidential terms or personally identifiable shopper data. Label every split as an estimate with its basis; never present a source-of-volume percentage as measured unless I supplied it.
Why it works — Innovation cases are routinely approved on gross forecasts and judged on net results. Making cannibalisation an explicit, monitored output — with a watchlist you can read weekly — aligns the approval conversation with the metric the business will actually be held to.
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