Walmart, the nation's largest retailer, has perfected a "just-in-time competitive strategy." This retail giant relies on barcodes for instant inventory, distribution centers that purchase supplies at the last minute and deliver only when needed, a small core of suppliers that Walmart can pressure for large discounts, routinized work that requires on average seven hours of training, and part time workers who often work full time hours without getting corresponding benefits. How does this 'just-in-time" approach change the mix of fixed and variable costs to the advantage of Walmart?