Segment sizing: How many of your target buyers can you actually reach?
A low-sugar tea launch shows how to size a reachable audience from household purchases and store availability, with a range when stock is unknown.
For a product launching through one retailer, count the target households that can find the exact pack at a store they use. Start with category buyers, apply the segment criteria, then check where those same households shop and whether the pack is on the shelf. Each step needs evidence about the households still in the count.
Start with the same households at every step
A beverage team is deciding whether one grocery chain can support a shelf pilot for a four-pack of low-sugar ready-to-drink tea. The counts, stock assumptions, and pilot target below are illustrative.
The team defines category buyers as households in the pilot area that bought ready-to-drink tea in the previous 90 days. An eligible household bought at least one tea with five grams of total sugar or less per 12 ounces during that period. The retailer step requires at least two shopping trips to the chain in the same period. For availability, the team wants the exact four-pack in stock and visible in at least three of four weekly shelf checks at one or more of the household’s usual branches.
Step | Households, base, and evidence |
|---|---|
Bought ready-to-drink tea | 50,000 category buyers in the pilot area · Household panel covering the category across retailers |
Meet the low-sugar purchase criterion | 15,000 of 50,000, or 30% · The same households’ receipts matched to product nutrition data |
Shop the launch retailer | 6,000 of 15,000, or 40% · Branch visits for those eligible households |
Can find the four-pack | 3,600 of 6,000 at 60% assumed availability · Planning assumption to replace with stock records and shelf checks matched to usual branches |
Use one household definition throughout and count a household once even when it shops at several branches. If you use a weighted panel, carry the weights through each step and keep the underlying sample sizes beside the projected counts. A national low-sugar purchase rate and a separate chain penetration rate leave the overlap unknown. Measure the two conditions together in the pilot area.
Match the exact pack to stores buyers use
Ask the retailer for its planned listings by store. Before launch, count the eligible households that shop at those stores. That is your upper bound for access through their usual branches. Once the pack is on sale, get dated stock records and check shelves at branches that serve the most eligible shoppers, including the times they normally visit. Match the identifier for the four-pack so the presence of a single can or another flavor cannot satisfy the check. GS1’s guide to product identifiers
A share of branches carrying the pack describes store distribution. To estimate household access, connect the stock checks to shoppers’ usual branches. A chain might stock the pack at a few busy stores that serve most of the target households. The same number of listings at quieter branches would produce a different estimate.
We can compare which pack or message different simulated groups would consider. That helps you choose a segment and offer to investigate. Use the purchase panel and store records for the count of households the launch can serve. Our audience segmentation research guide
Find the stock assumption that changes the pilot
If branch availability is unknown, keep the 6,000 eligible chain shoppers fixed and vary the share who can find the pack. At 40%, 60%, and 80% availability, the team can reach 2,400, 3,600, and 4,800 households respectively. Record 2,400 to 4,800 as a planning range tied to those assumptions.
A pilot that requires access to 4,000 households needs at least two-thirds of the 6,000 eligible chain shoppers to have reliable access. The middle case is 400 households short. Copy the worksheet with your own sources and check branches with enough target households to change the decision. If the confirmed count falls short, identify which additional branches would close the gap. Once access is established, measure trial and repeat purchase separately. Our market entry research guide
