Blue Cross Blue Shield's decision last week to vastly expand its Alternative Quality Contract — which rewards doctors for how well they care for patients, not just how many procedures they perform — is good news for an industry plagued by rapidly increasing costs. Experts have long contended that global payment systems such as the Alternative Quality Contract are the best way for health insurers to cut costs and deliver higher quality care. Blue Cross Blue Shield's experiment will show whether that theory works on a large scale. If it does, other insurance companies should follow. Traditionally, health insurers have paid doctors a set amount for each procedure they perform.