Glossary
What is goal-gradient effect?
The goal-gradient effect is the observed tendency for people to accelerate their effort as they get closer to a reward, which is the psychological mechanism a stamp card relies on.
This is why visible progress matters more than reward size. A customer at eight of ten stamps visits more frequently than the same customer at two of ten, even though the reward is identical. It is also the argument for wallet cards over paper: the card shows current progress on the lock screen, so the customer is reminded how close they are without having to look for a card.
What does the goal-gradient effect predict?
That customers visit more often as the reward approaches, and least often just after starting. The practical consequence is that a threshold must be visibly reachable, because a customer who cannot see the finish line never enters the acceleration phase at all.
How is it used in practice?
By making progress continuously visible and by starting customers above zero. A wallet card does the first by default, since the stamp count sits on the lock screen rather than in a drawer.
The second is endowed progress: a twelve-slot card with two stamps pre-filled outperforms an identical ten-slot card that is empty, even though both require ten more purchases. Progress already made feels like something worth protecting.
What does it explain about paper cards?
Why losing one is so damaging. A customer two stamps from a reward was in the acceleration phase; after the loss they are further from the reward than when they started, and the effect that was driving their visits now works against re-entry.
See also
- Reward threshold: The reward threshold is the number of stamps or points a customer must reach before earning a reward, and setting it correctly determines whether the programme motivates or discourages.
- Stamp card: A stamp card is a loyalty mechanic that rewards a fixed number of visits, one stamp per visit (buy ten coffees, get the eleventh free), and is the digital successor to the paper punch card.
- Wallet card: A wallet card is a digital card stored in Apple Wallet or Google Wallet (the same place people keep boarding passes, event tickets and payment cards) that can update itself remotely after it has been issued.
- SMS enrolment: SMS enrolment is signing a customer up to a loyalty programme by taking their phone number and texting them the card link, so the customer does nothing at the counter but receive a message.
Further reading
Why paper punch cards fail, and what to replace them with
Paper loyalty cards lose customers for three structural reasons. Here is what each one costs and how a wallet card fixes it.
How many stamps should a loyalty card have?
Setting the reward threshold too high kills motivation and too low erodes margin. Here is how to pick the number for your business.