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Issues: Informative Censoring
Possibility that impending event causes informative
censoring (confounding?)
•Types
of variables
–Extrinsic:
Unaffected by individual decisions
•As
a rule, time-varying extrinsic variables will not cause informative
censoring
•E.g.,
Air pollution on a given day in an asthma study
»(providing
it does not affect relocation)
–Intrinsic:
Potentially affected by impending event
•E.g.,
Marijuana use