hesela.devLeft-truncation
Left-truncation is selection into a time-to-event sample only after a unit has survived to its observation-entry time.
A drive already several years old at the start of a study enters the observed risk set at that age, not at birth. Drives that failed before entry are absent. This differs from right-censoring, which limits follow-up after entry, and from an unknown or missing age value. Models for a lifetime-from-birth question must account for delayed entry under their stated assumptions.
Relations
- related
- right-censoring, hazard-rate, drive-day