PITCHf/x, created and maintained by Sportvision, is a system that tracks the speeds and trajectories of pitched baseballs. This system, which made its debut in the 2006 MLB playoffs, is installed in every MLB stadium. The data from the system is often used by broadcasters to show a visual representation or the pitch and whether or not a pitch entered the strike-zone. PITCHf/x is also used to determine the type of pitch thrown, such as a fastball, curve, or slider. MLB uses the data from PITCHf/x in its Zone Evaluation System which is used to grade and provide feedback to umpires. Sabermetric analysts note that umpire accuracy has improved after the technology was introduced to MLB.