Trial and repeat purchase: Did your launch bring shoppers back?
The first order starts the clock. Group buyers by when they tried the product and give each group the same time to come back before comparing repeat.
Measure repeat purchase among first buyers who have had the same amount of time to buy again. Keep the price they first paid and the stock they could find visible so you can decide whether to investigate the product, the offer, or access.
Say Fieldglass launches a canned iced tea at one grocery chain. The team wants to know whether households that buy one can return for another paid purchase. In this worked example, the team uses 28 days after each household’s first purchase because that window fits the expected buying cycle for this product. The brand and counts are illustrative. A product that lasts longer will need a different window. NIQ’s consumer panel approach to trial and repeat
Start the clock at the first paid purchase
Use a consistent buyer identifier in the data you are permitted to analyze, such as a household ID in the retailer’s loyalty records. Trial is the first paid purchase of the specified product observed for that household since launch. Repeat is a paid transaction for that product on a later day within the chosen window. Two cans in one basket are one trial occasion. Name the product definition and retailer coverage so a reader knows which transactions the data can see.
Group first buyers by the week they tried the product. Each household has its own 28-day clock. Include a cohort’s rate once all households in it have had that full observation period. Keep newer cohorts visible as pending. Calculate the rate by dividing the number of households with a paid repeat by the number of first-buying households with a complete window.
Read the counts alongside the rate
First purchase cohort | Paid repeat and complete 28-day base |
|---|---|
Week 1 · introductory price · some stock gaps | 24 of 120 households · 20% |
Week 2 · regular price · no recorded stock gaps | 24 of 80 households · 30% |
Week 3 · regular price | Pending · 60 first buyers · Window still open |
Mature cohorts combined | 48 of 200 households · 24% |
Weeks 1 and 2 have the same number of repeat buyers. Week 2 has the higher rate because fewer households tried the tea in the first place. The two weeks also differ on stock. Of the 120 week-one buyers, 40 shopped at a usual store with a recorded stock gap late in their repeat window. Four of those households came back, compared with twenty of the eighty whose usual store had recorded stock throughout that period. That is 10% versus 25% in the two groups.
The gap makes shelf availability the first thing to investigate. It could also reflect who shops at each store or the kind of shopper who first bought at the introductory price. Keep both groups in the headline rate and report the split beside it. Verify the stock records and check where buyers normally shop before attributing the gap to a missed buying opportunity.
Give the next question to the right team
Copy the cohort table into your launch review. For each row, keep the first-purchase dates, price or discount at trial, eligible household count, number with a paid repeat, and stock coverage during the follow-up. Keep different pack sizes separate if they last for different amounts of time. Combine rates by adding their counts and bases, as the table does for the mature weeks.
If repeat is low where the product stays in stock, talk to first buyers about what happened after opening the pack and what they bought next. If it is concentrated in stores that ran out, check supply and repeat the comparison once stores can keep the item on shelf. If the gap follows introductory-price buyers even in comparable stores, test whether the regular-price offer gives them a reason to return. That question belongs with the commercial team. Our CPG guide shows how those findings lead back to specific changes in the product, pack, or route to market. Our CPG market research guide
