Tier Number

SAS Name

Medicare Part D formulary tier identifier. This field represents the cost sharing tier in which the drug product was placed in the sponsor's formulary. This identifier is also a key that links a Part D sponsor's cost sharing tier record in the Plan Characteristics File to a prescription drug event record (i.e., the PDE data) using contract ID, plan ID, and tier ID.


For 2006–2009 this variable was found in the Part D Event Characteristics files. This variable is first available in the Formulary file in 2010. It is also present in the Excluded Drug file, starting with 2012 data. It can be joined to PDE using the combination of the plan's formulary ID (variable called FORMULARY_ID) and the CCW formulary drug identifier (variable called FORMULARY_RX_ID) to determine the placement of a particular PDE on the formulary (according to plan design). The value of this field may not exactly represent the beneficiary experience at the time of the prescription fill (e.g., no data are collected at the time of the transaction to indicate the actual beneficiary experience). The maximum number of tiers varied by year. The largest number of tiers was 9 (in 2007). From 2011–2020, only up to six tiers are possible; starting in 2021 plans are allowed to have up to seven tiers. The CCW constructs the Plan Characteristics file from information submitted by Part D plan sponsors to CMS’s Health Plan Management System (HPMS).

Values: 01-09

Source: CMS (HPMS Files)