MAS-I: Censoring contributes a survival probability to likelihood
An observed event at time t contributes a density or probability mass appropriate to the observation. A right-censored record tells you that the event has not occurred by t; it contributes a survival probability, not a density at t.
Worked example or practice scenario
With independent exponential lifetimes, one observed event at time 2 and one right-censored record at time 5 give likelihood λe^(−2λ) × e^(−5λ)=λe^(−7λ). The MLE is 1/7. Treating the censored record as another death would incorrectly give 2/7.
Try this next
Derive the log likelihood and its derivative. Record what is observed for each subject. Consider whether censoring is independent of the event process before applying the standard likelihood construction.
Reading sources
ActNet editorial guide · October 1, 2026 · Original illustrative examples.