As a context effect in consumer purchasing decision-making scenarios, previous research has often demonstrated that scarcity effects lead to increased purchase quantities when shelf availability is limited during brand selection. However, these findings are primarily based on laboratory studies, and research specifically examining consumer purchasing choices across entire product categories in real-world retail settings has been lacking. In this study, we investigated whether scarcity effects at the category level manifest during actual purchase situations. We measured shelf fulfillment rates and stop rates (the proportion of people passing by the shelf who paused for at least 3 seconds) using in-store cameras and analyzed point-of-sale (POS) data. Surprisingly, unlike brand selection scenarios, higher shelf fulfillment rates were associated with increased overall purchase rates across the entire category. Furthermore, the magnitude of this effect varied based on practicality and preference differences. We conducted theoretical discussions regarding these results.
