In competitive markets, do all purchasers have to be informed or switch in response to changes in prices and quality for markets to perform efficiently? Yes, otherwise changes in prices and/or quality will not cause a firm to lose many customers, patients, enrollees, or market share Depends on the type of market; it's not necessary in markets with homogeneous products (such as steel), but it's necessary in markets where the product is complicated (such as electronics) Depends on the type of market; it's not necessary in government price-regulated markets (such as Medicare) for everyone to be equally informed, but in nonregulated markets they need to be informed No, just like in other markets, the more responsive (price or quality sensitive) purchasers drive the market toward greater efficiency