Types of Censoring

About CensoringTypes

Censoring (Penyensoran): When the exact survival time is not fully observed—only partial information is available.

Event time is beyond a certain point.

Type I (Time Censoring): Study ends at a pre-determined time $τ$ .
- Fixed: All subjects stop at the same time $τ$
- Progressive: Different fixed censoring times $C_i$ assigned at start
Type II (Failure Censoring): Study ends when $d$ events occur among $n$ subjects.
- Simple: Stops at the $d$ -th failure
- Progressive: Some survivors removed at intermediate event times
Competing Risk: Multiple event types; one event prevents observation of others.

Event occurred before study started but exact time unknown.

Event known to occur within an interval $\[L, R]$ .

Dataset contains both left-censored and right-censored observations.

Feature	Censoring	Truncation
Nature	Missing information about exact time	Selection bias by study design
Awareness	Researcher knows subject exists	Researcher may not know excluded subjects exist
Likelihood	Uses $f (t)$ for events, $S (t)$ for censored	Uses conditional probabilities