Jan's Blog

Category: Programming

NONMEM ADDL Calculation and Compression in SAS

ADDL represents the number of additional doses that are copies of the current row, with the time since first dose (RTFD) increased at the regular dosing interval (II). This allows for the compression of dose records in the NONMEM dataset. To put it more eloquently: The NONMEM data item ADDL on a dose record expresses […]

SAS and the Forward Re-scan Rule

The “Forward Re-scan Rule” (FRR) is used by SAS to resolve macro variables over several passes. This is especially useful when having one macro variable point to another macro variable, or when trying to resolve numbered macro variables. The SAS Advanced Prep Guide summarises the FRR as follows: Example: numbered list of macro variables To […]

SAS LOCF For Multiple Variables

It is often necessary to replace missing measurements with the closest, previous measurement. This technique is referred to as LOCF (last observation carried forward). In this example, we will create a dataset with 4 columns: subject ID, visit number, body weight, and systolic blood pressure. Thereafter, we will sort the dataset to ensure it is […]

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