Date shift

Shift every date by a fixed offset, preserving intervals and times.

A single offset (in days) is added to every DA value and the date part of every DT value. Times are left untouched, so intervals between events and the time-of-day are preserved — the PS3.15 “Retain Longitudinal Temporal Information with Modified Dates” option.

Tip Auto derives a deterministic per-patient offset from PatientID, so all of one patient’s studies shift together.