Time-at-risk and censoring
Entry or time zero → risk window → outcome or censoring event → analysis time
Flow diagram
Steps
Entry and time-zero definition
Define delayed entry and alignment with eligibility/exposure if applicable.
At-risk observation window
Specify lag, start, end and recurrent-risk rules.
Outcome event
Define event time and adjudication rules.
Censoring event
Define administrative end, loss and other censoring conditions.
Competing event
Define events that preclude the outcome; choose the estimand-specific treatment.
Derive observed time and status
Apply event priority and tie rules consistent with the estimand.
Check follow-up and assumptions
Assess negative times, completeness and informative censoring.
Tables and supporting information
Time and status rules
Document competing-event handling rather than treating all endpoints identically.
Simple right-censoring notation
For a simple right-censored endpoint only: T is event time, C censoring time. Extend for delayed entry, competing risks or recurrent events.
Censoring assumptions
State the assumptions needed by the chosen estimator and how departures will be assessed.