Data Preparation and Outlier Trimming for Calculating DRG Relative Weights : A Technical Note to Inform Indonesia's DRG Grouper Algorithm (InaCBGs)

Overview & Synopsis

Checking, editing, and trimming of clinical and cost data are important steps in the process of designing or refining the DRG grouper algorithm and determining relative (cost) weights (RWs). The DRG grouper algorithm is designed and routinely refined to classify episodes of care into specific DRGs with similar clinical features and resource use. Careful assessment and editing of the data are essential to avoid errors and outliers that could lead to inappropriate DRG assignment or distortions in estimates of average costs used to determine RWs, which are multiplied by a base rate to obtain the payment amount or tariff. This technical note explains the basic data preparation and outlier‑trimming steps implemented prior to determining RWs and clarifies the difference between statistical outliers used for trimming and high‑cost outliers identified for payment purposes.