Ruma Kumar spent six months researching how Shelby County Schools used $90 million in funding from the Bill and Melinda Gates Foundation. Mostly, it paid for teacher training, evaluations, a streamlined hiring process and crucial data. Results have been varied, but overall promising. A 1-year extension on the grant will preserve this expensive training model for now. But with Shelby County Schools facing a major deficit, the district may have to reconsider the costs of training a better teaching staff.