Cross Validated
2023-01-25 17:35 UTC
By Prajwal Mani Pradhan
AI-113-20230125-social-media-80d4dc51
Correct way to calculate time to an event variable
Is this the correct way to calculate time to an event(death) for survival analysis? t2death column calculated using SQL as: case when death_dt is not null then death_dt - admission_dt else study_end_dt - admission_dt end as t2death The final data looks like: id time0 study_end_dt admission_dt death_dt t2death 1 2021-05-24 2022-08-31 2021-05-24 NA 464 2 2019-12-10 2022-08-31 2020-01-19 2020-01-23 4 3 2020-10-14 2022-08-31 2020-11-22 2020-12-03 11 4 2021-11-23 2022-08-31 2021-11-26 NA 278 My concern is that there is t2death value for id: 1, 4, but they are still alive. How does a survival analysis algorithm know that they have been censored? Any reading resources or explanation would be greatly appreciated.
Is this the correct way to calculate time to an event(death) for survival analysis? t2death column calculated using SQL as: case when death_dt is not null then death_dt - admission_dt else study_end_dt - admission_dt end as t2death The final data looks like: id time0 study_end_dt admission_dt death_dt t2death 1 2021-05-24 2022-08-31 2021-05-24 NA 464 2 2019-12-10 2022-08-31 2020-01-19 2020-01-23 4 3 2020-10-14 2022-08-31 2020-11-22 2020-12-03 11 4 2021-11-23 2022-08-31 2021-11-26 NA 278 My concern is that there is t2death value for id: 1, 4, but they are still alive. How does a survival analysis algorithm know that they have been censored? Any reading resources or explanation would be greatly appreciated.
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Cross Validated
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