In the context of survival analysis it is possible that increasing the value of a covariate X has a beneficial effect on a failure time, but this effect is reversed when conditioning on any possible value of another covariate Y. When studying causal effects and influence of covariates on a failure time, this state of affairs appears paradoxical and raises questions about the real effect of X. Situations of this kind may be seen as a version of Simpson's paradox. In this paper, we study this phenomenon in terms of the linear transformation model. The introduction of a time variable makes the paradox more interesting and intricate: it may hold conditionally on a certain survival time, i.e. on an event of the type {T>t} for some but not all t, and it may hold only for some range of survival times.

Simpson's Paradox in Survival Models / DI SERIO, C.; Rinott, Joseph; Scarsini, Marco. - In: SCANDINAVIAN JOURNAL OF STATISTICS. - ISSN 0303-6898. - 36:(2009), pp. 463-480. [10.1111/j.1467-9469.2008.00637.x]

Simpson's Paradox in Survival Models

RINOTT, JOSEPH;SCARSINI, MARCO
2009

Abstract

In the context of survival analysis it is possible that increasing the value of a covariate X has a beneficial effect on a failure time, but this effect is reversed when conditioning on any possible value of another covariate Y. When studying causal effects and influence of covariates on a failure time, this state of affairs appears paradoxical and raises questions about the real effect of X. Situations of this kind may be seen as a version of Simpson's paradox. In this paper, we study this phenomenon in terms of the linear transformation model. The introduction of a time variable makes the paradox more interesting and intricate: it may hold conditionally on a certain survival time, i.e. on an event of the type {T>t} for some but not all t, and it may hold only for some range of survival times.
Simpson's Paradox in Survival Models / DI SERIO, C.; Rinott, Joseph; Scarsini, Marco. - In: SCANDINAVIAN JOURNAL OF STATISTICS. - ISSN 0303-6898. - 36:(2009), pp. 463-480. [10.1111/j.1467-9469.2008.00637.x]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11385/5570
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