In-store bounce rate is the physical equivalent of a website visitor who lands on a page and leaves immediately: the shopper entered the category but never stopped to look at it.
Shoppermotion measures it by speed. A bounce happens when a trolley or basket crosses a category above the visual contact speed (45 cm/s) from entry to exit, and bounce rate is those trips divided by all trips that entered the zone (bounce rate article). Some studies use time thresholds instead: less than 10 seconds in a section in our flyer funnel analysis, or less than 5 seconds next to an end cap.
A high bounce rate is not always bad. In a destination category it usually means the aisle is used as a corridor, and shoppers who already know the brand they want bounce more: eggs showed a high bounce rate for exactly that reason. Read it together with purchase speed and engagement, and always check the time of day, because bounce rates rise sharply during rush hours.
Promotion type also matters: in one analysis, BOGO promotions had the lowest bounce rate (20.4%) and the highest engagement rate (60.4%) (measuring in-store promotions). Usual fixes for a high bounce rate are moving the category, changing the entry bay or placing a strong end cap at the entrance of the aisle.