The Tiered Fidelity Inventory (TFI) is a tool that schools use to measure the implementation of Tier 1, Tier 2, and Tier3 PBIS Implementation. School teams use the TFI tool to identify areas to improve upon throughout the year. At the end of the year, an external evaluator uses the TFI to determine a final score. The score/s on the TFI help determine PBIS achievement in either Bronze, Silver, Gold, or Platinum.