Two stamps left until a free coffee: a visible goal gives guests a reason to return. The psychology of stamp cards explains why progress matters and offers practical ideas for designing a card people want to complete.
What the café study found
The most important source on this isn’t marketing, it’s research. In 2006, Ran Kivetz, Oleg Urminsky, and Yuhuang Zheng published a study of the goal-gradient effect in the Journal of Marketing Research that, among other things, tracked real café customers over several months. The guests had a classic collector card: buy ten coffees, and the eleventh is on the house.
As guests got closer to the free reward, the gaps between purchases shortened. They didn’t buy at a steady pace: they sped up near the goal.
The goal-gradient effect: closer to the reward, faster back
Researchers call this the goal-gradient effect. In early experiments, rats ran faster as they approached food. Kivetz and his colleagues were the first to demonstrate the effect cleanly in real human purchase decisions.
For your card, closeness to the goal matters. One stamp gives little incentive. Eight out of ten makes the reward feel within reach. Guests need to see that progress. A card forgotten in a drawer, with an unknown count, cannot help.
A distant goal holds this effect back. Twelve stamps for something bought twice a month leave guests in the slow first third for a long time. Calculate a suitable goal for your business in “How many stamps should your card have?”.
The starter stamp: gifted progress pulls people in
Kivetz and his colleagues also studied the start of the card. They compared two groups:
- One group got a card with ten empty boxes: zero done, ten to go.
- The other group got a card with twelve boxes, two of which were already stamped, meaning ten real purchases to the reward either way.
Both groups had to buy ten times. Yet guests with two gifted stamps completed their cards faster. This is endowed progress: a head start given to you. The difference was the feeling of having begun: “2 of 12” instead of “0 of 10”.
Goal-gradient describes the growing incentive near the finish. Endowed progress describes the nudge at the start. Both favour a visible path that already feels underway.
What this means for your card
We draw three practical design ideas from these findings. Read more in the guide to loyalty programmes.
1. Make progress visible
The pull only forms if guests actually know how far along they are. On paper, that means a card people carry with them and look at. Digitally, the card lives in the phone anyway and updates itself after every stamp; in Apple Wallet a note also appears on the lock screen. One look in the wallet shows the progress, with nobody having to dig for a card. The pass shows the count as a number, such as “4 of 10”. Enough contrast between background and text keeps it easy to read. The page on how to design your stamp card shows how to set the colours.
2. Give away the first stamp
Instead of “0 of 10,” start guests at “1 of 11” or “2 of 12.” The real effort stays exactly the same, but the feeling changes: they’re already in. The best moment for this is the very first scan. Whoever sets up their card gets the starter stamp on the spot, and never walks away with a blank one.
3. Keep the goal reachable
The goal-gradient effect only works if the end is in sight. Do the maths on how often your guests actually come back: daily coffee with ten stamps is two weeks, perfect. With a haircut every six weeks, roughly 54 weeks separate the first and tenth stamps. Choose a shorter target there. For how that looks in a café, with the reward and the rhythm, see the page on the coffee shop loyalty card.
Keep it honest. A starter stamp helps people begin. The reward must be real and the path fair. Guests quickly notice an artificially stretched goal, and the incentive can turn into frustration.
Frequently asked questions
What exactly did the Kivetz study measure?
In 2006, the researchers studied real café cards: buy ten coffees, get the eleventh free. As the reward approached, gaps between visits shortened. A second comparison found that gifted starter stamps led to faster completion, despite requiring the same number of purchases.
What’s the difference between goal-gradient and endowed progress?
Goal-gradient means motivation rises as the goal gets closer. Endowed progress is the head start, such as 2 of 12 instead of 0 of 10, that helps people stay with it. Both favour visible progress and a small head start.
How can I apply this to a digital card?
Make progress visible and choose a reachable target. The study did not test Treubar cards, so compare the gaps between visits in your own shop. A loyalty card in Apple Wallet & Google Wallet shows guests their current progress on their phone.
Ready to put these ideas into practice? Design your first card with Treubar and start with up to 20 customer passes on the Free plan.
Source
Kivetz, Ran; Urminsky, Oleg; Zheng, Yuhuang (2006): Goal-gradient study, Journal of Marketing Research, 43(1), pp. 39–58. DOI: 10.1509/jmkr.43.1.39 · Full text at Columbia Business School (PDF).