"Mercadona is unique in several ways,” says Zeynep Ton of Harvard University, who wrote a case study on the chain. Its 63,500 employees are on permanent contracts (with bonuses), work regular hours and receive 20 times more training than the staff of an average American retailer. This makes them more productive: sales per Mercadona employee were 18% higher in 2008 than at other Spanish supermarkets. Staff turnover is only 4% a year. Employees constantly gather feedback from shoppers, whom they refer to, accurately enough, as “bosses”."

— Mercadona: Spanish aisles | The Economist