Scarcity is the tendency to value what is limited: a deal that won't return, an offer that ends on a date, a quota that is nearly used. On this site most good examples are honest limits made visible, like "15 messages left" next to an Upgrade button.
In Worchel, Lee and Adewole's classic 1975 study, 200 students rated the same cookies as more desirable when the jar held 2 rather than 10, and more so when the supply had just dropped because of demand. The evidence base is older and mixed, with small lab samples, so treat the effect as real but variable. The bigger product risk is misuse: Mathur and colleagues crawled about 11,000 shopping sites and found 632 low-stock messages and 47 high-demand messages, some shown on every product regardless of stock.
For freemium products, scarcity is usually a usage quota rather than a stock count. Showing the remaining allowance as it drops, and putting the upgrade option right next to it, makes the limit concrete at the moment it bites. A one-time offer on a paywall works only if it really is one-time.
How to use it
- Show remaining quota in plain numbers ("14 of 20 left today") and update it immediately after use.
- Place the upgrade option next to the quota, not on a separate page.
- If an offer has an end date, state the date and keep it visible after the paywall is dismissed.
Watch out
- Fake low-stock or "only today" claims that reset on reload are deceptive and are under regulatory scrutiny.
- Making the free tier feel stingy on day one, before users have seen any value, pushes them away instead of up.
